Kourtney Kardashian admits she was a "little b***h" to sister Kim when they were kids.
The 34-year-old reality TV star was always bossy towards her sibling, who is 18 months her junior, when they were younger and didn't even appreciate it when Kim threw her a surprise birthday party.
Kourtney said: "When we were growing up, I could boss Kim around! Once she threw me this party with all my friends at a house in Palm Springs and when I got there everyone was like: 'Surprise!' and I was such a little bitch to Kim.
"The whole weekend I was really mean to her. I was such a bossy older sister!"
The brunette beauty - who has children Mason, four, and Penelope, 18 months, with partner Scott Disick - gets on much better with her sister these days, though they still row about clothes.
She told Now magazine: "It's so stupid and catty I know, but we've done it our whole lives. We're only 18 months apart, so we've always shared our clothes. It caused so many fights growing up. Thank God we don't wear the same size shoe!"
Though she is the eldest in the family, Kourtney admits her 29-year-old sister Khloe acts like the most responsible.
She said: "Now I think I sometimes play the younger sister, while Khloe plays the eldest.
"With Khloe, a lot of the times she'll try to act like she has it all going on and she's so tough.
"Sometimes when we travel together, she's like: 'Come on, little girl,' and she talks to me like I'm six. It's really funny. We all kind of have our roles - it's cool."

Simon Cowell has been practicing for fatherhood with a doll that wets itself, says Sinitta.
The 'X Factor' boss and his partner Lauren Silverman are expecting a baby, and his ex-girlfriend has opened up about how he is preparing for life as a dad.
She told The Sun newspaper: "He and Lauren got my daughter Magdalena a doll that can cry and do a wee-wee.
"It was funny watching him sitting there with it. One minute he'd turn it one way and it would start crying, then he'd turn it the other way and it would wee on him. He didn't know what to do."
Meanwhile, Sinitta added her former flame was still trying to get used to being around babies when she shared a holiday with him and Lauren in Barbados.
She said: "Someone handed him a baby to hold on the beach and I've never seen anything so awkward and ridiculous in my life.
"He didn't know one end from the other."
The dad-to-be has previously discussed the upcoming birth, and has already start to look at way of making his home 'baby-proof'.
He explained: "There are a lot of boring things that happen when you have a baby.
"You have to get rid of sharp edges, cigarettes, alcohol ... then there's the toilet to make safe. But I'll have a smoking room!"

Justin Bieber acts out to impress his father, according to a close family friend.
Cory Bernier - who is called 'uncle' by the star who he saw grow up - has insisted the 'Beauty and a Beat' singer is desperate to gain his dad Jeremy approval.
Speaking to the Daily Mirror newspaper, he claimed: "Justin has a very good heart but his judgement is being clouded by drugs and alcohol and a lot of it is to impress his dad."
Cory also insisted while the 19-year-old singer's family are "concerned" for the star - who was charged with drink driving, resisting arrest and drag racing in Miami in the early hours of Thursday morning (23.01.14) - he is emulating Jeremy's own "ego".
He added: "The family is concerned about Justin but they don't believe he has a problem.
"He walks around without a shirt on but that's just ego - and that's his dad's ego too."
Meanwhile, the star's recent wild behaviour is said to be the result of taking steroids.
According to reports in The Sun newspaper, sources close to Justin believe fat-burning drug Clenbuterol could be behind his rage.
An insider said: "As well as drinking and smoking weed, Justin's been taking steroids to give himself a six pack.
"His physique had gone from boy-like to muscled in a very short time and his moods have become wildly erratic."

Rihanna wants to give Cara Delevingne a self-portrait as a sign of their friendship.
The 25-year-old singer has commissioned street artist Bambi to create a giant painting of her best friend as a present for the supermodel and her family.
A source told the Daily Star newspaper: "Rihanna wanted to show Cara how important their friendship is to her. It will be a gift for both her and her family.
"Bambi came up with the concept, which is inspired by Andy Warhol's famous image of Debbie Harry, and Rihanna loves it.
"She even asked Bambi to do the painting on an old piece of metal, so it looks completely unique and quirky. The artwork is yet to be delivered but will go straight to Cara's family home where it will probably stay."
The 'Diamonds' hitmaker was able to contact the artist - whose identity has been kept a secret - because she knows the mysterious pop star personally.
And despite the painting carrying a big price tag, Rihanna is said to be willing to pay for the special gift.
The insider added: "The painting will cost around five figures but Rihanna doesn't mind spending that. Cara's one of her closest allies."

Kim Kardashian and Kanye West have asked Lady Gaga to sing at their wedding.
The couple - who have a seven-month-old daughter North - are expected to marry in Paris, France in the summer and it is said they are keen to have the 'Applause' hitmaker perform at the upcoming nuptials.
An insider told The Sun newspaper: "Kim and Kanye met up with Gaga in Paris.
"They were desperate to get the star's involvement, which is why she's the first person to be asked.
"She's ideal for them because Kanye has always been a fan of her style and performance art. But also, Kim loves her music, so it's one they can instantly agree on."
The two stars will have to keep searching for a venue for the wedding though, after they were deemed "not classy" enough to get married at the Palace of Versailles.
A source recently added: "Kim and Kanye really wanted to get married at Versailles and were hoping to persuade officials during their visit.
"But ultimately it backfired. It was still a firm non. They will now be scouting private estates and chateaux in the region."

Demi Lovato says Selena Gomez is "doing really well" after Justin Bieber's recent arrest.
The two stars are close friends, and she has spoken of how the 'Beauty and a Beat' hitmaker's on/off girlfriend is coping after he was charged with drink driving, resisting arrest and drag racing in Miami in the early hours of Thursday morning (23.01.14).
Talking to 'On Air With Ryan Seacrest', Demi said: "We have an incredible friendship ... [Selena] is strong! She's doing really well right now!"
The 21-year-old singer revealed she and her fellow former Disney star had met up for a heart-to-heart talk following Justin's arrest, but she refused to go into detail about their conversation.
She added: "We're really, really close ... And, any advice I had for her, we talked last night and - you know - it's between us. But I love her so much."
It was recently reported many members of Justin's entourage wanted to keep him away from Selena after allegedly told him to go to rehab and has been leaving him "hanging".
A source previously claimed: "The message has been sent. There is always so much - ridiculous - drama involving both of them.
"They fight constantly and Selena loves to keep Justin hanging. He always acts out after they fight. Selena is just not good for Justin. They need to stay away from each other."

Robbie Williams has rejected the chance to return to his hometown for his birthday celebrations.
The organiser of a party in his honour has said the offer to attend was snubbed because he is too "busy" with his music career.
Martin Tisdewell told The Sun newspaper: "We wrote to Robbie to ask his permission to host these events.
"He said he was delighted but because of his busy tour schedule it is unlikely that he will be back to Stoke this year."
Locals in Stoke-on-Trent have organised a month of events to celebrate his 40th on February 13 as part of the Robbie Day Festival which will include renaming three streets after his songs.
According to reports in The Sun newspaper, the road names will be Angels Way, Candy Lane and Supreme Street, while bus tours will be organised to travel to landmarks associated with the former Take That singer.
While the local community with be coming together to celebrate the star, one resident struggled to accept he wouldn't "have any free time" to come back to his hometown.
They said: "It's a bit hard to believe that he doesn't have any free time in 2014 at all."

Ethan Hawke and Uma Thurman reunited for a skiing trip with their children.
The former couple, who split in 2003 after five years of marriage, were spotted enjoying some time on the slopes with their daughter Maya, 15, and son, Levon, 12, after they met up at the Sundance Film Festival in Park City, Utah.
An eyewitness said: "They seemed very comfortable. They looked like a normal, happy family. No tension."
A source told UsMagazine.com that the duo, both 43, also had lunch with their children at the Stein Eriksen Lodge.
Ethan and Uma have both moved on and had other children since their split.
The 'Boyhood' star has two daughters, Clementine, five, and Indiana, three, with his wife Ryan Hawke, whom he married in 2008.
Meanwhile, Uma has an 18-month-old daughter Rosalind with her on/off boyfriend Arpad Busson.
Ethan, who previously claimed he had no business marrying Uma when he was 27 because he was too immature, recently said he doesn't believe in monogamy but insisted he had no regrets about marrying the blonde beauty after meeting her on the set of 'Gattaca' in 1996.
He said: "We tried to be as optimistic as we could be: we all want to believe in love and the possibility of love. The older you get, the more you realise how powerful love is. You understand the right ways for emotion to lead your life and the dangerous ways. I don't regret marrying early."

Jennifer Hudson does mini workouts in her kitchen.
The Weight Watchers spokesperson, who lost 80 pounds by following the diet programme a few years ago, doesn't always have time to work up a sweat in the gym and uses her oven to time her exercises at home.
The 32-year-old 'Spotlight' hitmaker told PEOPLE magazine: "Sometimes I set the timer on the stove and run up and down my steps until it goes off. You don't even need to go to the gym. Set the timer or microwave for 15 to 20 minutes and you'll work up a sweat."
Jennifer, who has a four-year-old son, David, with her fiancé David Otunga, is currently trying to get her fitness routine back on track after splurging on calorie-laden treats over the festive season.
She said: "I cheated my life away over the holidays. I fixed my son brownies and chocolate chip cookies every day of the holiday season, and Mommy had some too. Several times I went over my points, and it's good to allow yourself that. If you don't give that, that's when you rebel."
The Oscar-winning actress wants to be in good shape for her wedding but recently admitted she keeps pushing the date back.
She said late last year: 'Yes, there was a date set, and that date has come around again every year. In fact, the date may keep rolling around ... When I'm ready to be married, I will be married. It's that simple. Everyone should just chill. Our relationship is very strong. We're both huge family people, and I'm only going to get married once. So I'm not rushing into anything.''

Justin Bieber was driving under the speed limit when he was arrested.
The 'Heartbreaker' hitmaker, who was charged with drink driving, resisting arrest and drag racing in Miami, Florida in the early hours of Thursday morning (23.01.14), was reportedly only driving at 27 MPH in the middle of his "drag race."
A source told gossip website TMZ.com that the 19-year-old star, who was accused of driving between 55 and 60 MPH in a yellow Lamborghini alongside his friend Khalil in a Ferrari for 15 blocks, had a GPS device installed in the rental cars that tracks speed and it proves both cars were only going 27 MPH at the 3500 block of Pine Tree Drive in the middle of their alleged "drag race."
Only one of the cars broke 50 MPH once during the short rental period and it was after the singer and his entourage left a nightclub a few hours earlier.
Police officers also claimed Justin, who is more than a year under the legal drinking age in the US, reeked of alcohol at the scene but his blood alcohol level was barely measurable at .014.
Meanwhile, Justin finally flew out of Miami on Friday night (24.01.14) after refusing to board a private plane that had been organised to take him back to Los Angeles so he could enter rehab after he was released from jail on Thursday.
His security team were forced to sneak him out the back of his rented mansion in South Beach due to the huge amount of fans waiting to greet him.

LL Cool J isn't nervous about hosting the Grammy Awards on Sunday (26.01.14).
The 46-year-old rapper is set to present the glitzy annual ceremony for the third time at the Staples Centre in Los Angeles and said the opening performance will be "crazy."
He told Parade.com: "You gotta embrace it with grace. I don't go out there pretending I'm Billy Crystal. I have to be myself."
Asked what fans can expect from the show, he also told 'Entertainment Tonight': "Definitely don't miss the opening. The opening is going to be crazy."
Beyoncé is believed to be preparing to open the show with her husband, Jay Z, but the 'NCIS: Los Angeles' star refused to confirm the rumours.
He said: "I can't confirm or deny that. But I will tell you, like I said, don't miss the opening."
But the 'Doin' It' hitmaker is looking forward to seeing newcomer Lorde on stage as he can relate to her.
He explained: "I was 16 when I started at Def Jam, so I can relate to what she's going through. It can be a very exciting and confusing time. It takes a mature person to stay grounded. And in this age, the criticism can be brutal."
Madonna, Katy Perry, Robin Thicke, Chicago, Kendrick Lamar and Imagine Dragons as well as legendary The Beatles musicians Sir Paul McCartney and Ringo Starr will also perform at this year's Grammy Awards.

Heidi Montag claims her cosmetic surgeon made her feel very insecure.
The former 'The Hills' star, who underwent ten surgical procedures in one day in early 2010, including a brow lift, liposuction and two breast enlargements, originally only wanted to tweak her appearance and had no idea how much pain going under the knife would cause her.
The 27-year-old star, whose plastic surgeon Dr. Frank Ryan died in a car accident in August 2010, told Barbara Walters on 'The View': "I really just went back in to get my nose reset and get a little bit larger of implants because I had been elbowed by a backup dancer in a music video that I was doing and then I went in and was talking to my doctor and he just kind of diagnosed me and was like, 'You should get a chin reduction, and an eyebrow lift.'
"I didn't know what an eyebrow lift and a chin reduction was! So once he kind of told me everything that was wrong with me I felt really insecure, and he gave me a really great deal on it all. He didn't tell me how extensive it was going to be, how severe, how painful, so I had no idea."
Heidi had her breast implants reduced in size last year and now lives a much simpler life with her husband Spencer Pratt after blowing their $10 million fortune.
She said: "We just live really humble lives. I cook a lot, I clean our house all the time."
The couple, who live in Los Angeles, hope to have children when their lives are more stable.
Heidi said: "First our priority is really getting a career and being stable because especially Spencer wants to be very responsible with it... To have security for our children."