Miley Cyrus has slammed Katy Perry on Twitter.
The pair locked lips when Miley performed in Los Angeles recently, but Katy said on Australian TV earlier this week she pulled away when 'Wrecking Ball' star tried to take it further, saying: "God knows where that tongue has been. We don't know! That tongue is so infamous!"
Miley, 21, hit back on Twitter today, slamming notorious ladies man John Mayer, who recently split with Katy.
She wrote: "Girl if ur worried abt where tongues have been good thing ur ex boo [boyfriend] is ur EX BOO cause we ALL know where THAT [tongue] been (sic)"
Trying to soften the blow, Miley then added: "Dontchyouuuu act like you didn't lurvvvvv it @katyperry (sic)"
After their kiss on February 22, Katy shared an aftermath photograph, which features the '4x4' singer with her mouth hanging open in shock and Katy covering her mouth with her hand, and captioned it: "And after! I adore you @Miley Cyrus."
Katy, 29, and John split last month, blaming their conflicting schedules, but since then friends have accused the guitarist of "sketchy" behaviour.
A source said: "The last time they broke up John won [Katy] back by making a ton of promises. He was going to put her first, but now he's falling back into his old patterns.
"Like, he shuts off his phone and disappears all day and night - he says it's because he needs alone time, but it's sketchy for sure."

Matthew McConaughey's hat from 'Dallas Buyers Club' is being auctioned off.
The actor wore the white Resistol brand hat throughout filming of his Oscar winning performance as AIDS patient Ron Woodroof in the movie, and it is now up for auction with a starting bid of $3,000.
The hat is signed under the brim, where Matthew has written in black marker pen: "Just Keep Living, Matthew McConaughey.''
The hat is a size 7 and 3/8 with a 4-inch brim and made in Texas. The headwear - to be auctioned in Los Angeles by Nate D. Sanders - comes with a certificate of authenticity from Universal Pictures.
Matthew isn't the only star to auction off hit hat this week, as Pharrell Williams sold the hat he wore to the Grammy Awards - a bold Vivienne Westwood Buffalo style piece, which became a talking point at the music ceremony last month - for $44,100.
The hat was snapped up by fast food chain Arby's and the money raised will benefit Pharrell's teen charity One Hand to Another.
After the auction had closed, Pharrell wrote on Twitter: "Thank you to whoever bought my Grammy hat on @eBay for $44,100. Your donation benefits From One Hand to Another. (sic)"
Arby's - whose corporate logo is a 10-gallon hat, bearing a strong resemblance to the one sported by the singer - jokingly tweeted back: "You're welcome. We're HAPPY to support a great cause & get our hat back."
To bid on Matthew's hat visit tinyurl.com/kyc9pru

Khloe Kardashian has bought Justin Bieber's house.
The reality TV star has splashed out on the mansion in gated community The Oaks, located in Calabasas, California, according to Us Weekly.
Justin put the house on the market late last year after a number of run-ins with his neighbours, culminating in a raid by the local sheriff's department after the property of one of the singer's neighbours was egged, causing up to $20,000 of damage.
Security footage from Justin's mansion was removed and his friend, Xavier Smith - also known as Lil Za - was arrested for drug possession.
The Los Angeles County District Attorney is now reviewing evidence and deciding whether to press charges against the 'Confident' star.
Speaking of their most famous resident in January, Calabasas mayor, Fred Gaines, said: "The peace and privacy of our residents is the city's top priority. We have unfortunately had a number of breaches of the peace related to Mr. Bieber and his residence, and the sheriff has acted appropriately in addressing those incidents."
Justin, 20, is now renting a house in Atlanta, Georgia, with a view to buying a property and moving to the city full time.
Khloe is moving after selling the marital home she lived in with estranged husband Lamar Odom in nearby Tarzana in January.
The house was bought by 'Big Bang Theory' star Kaley Cuoco, for $5.5 million.
Khloe's sister, Kourtney, has also bought a property in the same gated community, meaning they will soon be neighbours.

Hayden Panettiere has "always dreamed" of her wedding day.
The 'Nashville' actress is engaged to boxer Wladimir Klitschko, 37, and though they haven't yet started planning their nuptials, she already has some ideas of what she wants for her big day.
She told People magazine: "I have always dreamed of a wedding day! Not over the top or crazy, but yeah, I've always thought about it.
"It's one of those things you have to just cross your fingers and hope everything will go smooth. You will plan and plan and at the end of day you just have to kick back and see what happens."
The 24-year-old beauty also admitted she is embarrassed by some of her teenage pictures because she had such bad hair cuts.
She said: "Some of my school pictures when the crunchy hair was in, you would get out of the shower and put the most intense gel you could find in your hair. Welcome to my 8th grade picture -- my mom was pleased. You could blow on your hair and it would snap in half.
"And then I dyed my hair red once, which was also a terrible idea. It washed out into a lovely orange. It was a very unattractive part of my life."

Leonardo DiCaprio caught up with former girlfriend Gisele Bunchen at Madonna's Oscars party.
The 'Wolf of Wall Street' actor was accompanied to the bash on Sunday (02.03.14) by current partner Toni Garrn but the model reportedly "sat back" to allow him to chat to the Brazilian beauty, who he had a five-year on/off relationship with until 2005.
And Leonardo and Gisele - who has children Benjamin, four, and Vivian, 16 months, with husband Tom Brady - weren't the only former couple who caught up at the bash, which was held at Madonna's manager Guy Oseary's Californian home.
Miranda Kerr and Orlando Bloom - who split last year after three years of marriage - were also there and the source told the New York Post newspaper that they "seemed on good terms."
Meanwhile, host Madonna made sure she was the centre of attention.
The source said: "She was literally grinding the dance floor."
Earlier in the evening, Orlando had surprised Miranda - with who he has three-year-old son Flynn - by interrupting as she gave a TV interview on the red carpet at the Vanity Fair party.
In a touching display of affection, the actor planted a kiss on her cheek and quipped, "Hi. You look amazing", as a flustered Miranda tried to regain her composure for the cameras.

Shailene Woodley can fall in love with men or women.
The 'Divergent' star refuses to limit herself to one sex when it comes to dating and is instead attracted to people's personalities.
In an interview with The Hollywood Reporter, she confessed: "I fall in love with human beings based on who they are, not based on what they do or what sex they are."
Shailene has been romantically linked to her 'The Spectacular Now' co-star Miles Teller but she insists they have more of a brother and sister type of relationship.
She said: "I would say we have like a sibling relationship but with moments of sexual tension."
The 22-year-old actress' open attitude to relationships also extends to her views on sex scenes.
Shailene - who appears nude and in a variety of erotic scenes in 'White Bird in a Blizzard' - is prepared to strip off and act out lovemaking on the big screen if the role requires it and believes it is her responsibility as an actress to make the scenes as realistic as possible.
She explained: "When somebody's doing a sex scene and they're wearing a bra and underwear, that's not how it happens in real life. If I'm going to say yes to a movie where this is necessary, then I'm going to bring truth to that situation."

An intruder has been arrested inside Justin Bieber's home.
Qianying Zhao - who stands 5'5" and weighs just 110 lb - was discovered sleeping in a bedroom inside the pop star's Atlanta home by the niece of the property owner yesterday (05.03.14).
She called police, who woke the woman and, when questioned, the alleged trespasser claimed she had met the 'Beauty and a Beat' hitmaker on twitter and was visiting him for a birthday party.
When she realised she was too late for the party, she instead found an open door and decided to let herself in to wait for the 20-year-old singer.
According to gossip website TMZ, Zhao was arrested for criminal trespass and placed into double-locked handcuffs with her hands behind her back.
It is unclear whether Justin - who moved to Atlanta recently following a string of incidents and rows with his neighbours in California - was at home at the time of the incident.
Meanwhile, the 'Believe' hitmaker has broken another record, as his 2010 single 'Baby' has racked up over a billion views on YouTube.
The video-sharing website posted on their twitter page: "Congratulations to @justinbieber and all the #Beliebers who propelled "Baby" to its billionth view on YouTube.(sic)"

Britain's Prince William and Duchess Catherine arrived in the Maldives this morning (06.03.14) for a romantic getaway. The royal couple are thought to have landed on a British Airways plane at 9.40am local time and will be staying at a newly-opened pr...

Wild Beast's Tom Fleming says bands have to have a "certain amount of arrogance" to be successful.
The band released their first single 'Brave Bulging Buoyant Clairvoyants' in 2006 but became better known after being nominated for a Mercury Prize for their 2009 album 'Two Dancers', and bassist Tom Fleming thinks bands have to be slightly arrogant in order to do well.
He said: "I don't think the world has got to be any fairer or better a place since we've been making music but I think we still feel - as any good band or artist should feel - that it is you against the world.
"You have to have a certain amount of arrogance mixed with absolute terror that it may or may not work. But that's the good part, that's the exciting part."
Tom and his bandmates' - Hayden Thorpe, Ben Little and Chris Talbot - other albums include their 2008 debut 'Limbo Panto', 2011's 'Smother' and 'Present Tense', which was released last month, and he claims they've never been a "yeah, oh baby" kind of band because their lyrics are important to them.
He told XFM Radio: "I think a lot of our favourite songwriters are lyricists as well. I think lyrics are an instrument. They are supposed to add to a whole - whether those lyrics sound appropriate or inappropriate - lyrics are supposed to have a musical aspect to them too rather than just being words that mean something."

Charlotte Church performed a sci-fi themed concert in London on Wednesday night (05.03.14) to launch her new release 'FOUR'.
The special concert at London's Riverside Studios saw Charlotte don UV face paint and wear a gown with tentacles made of LED lights as she played with her band, who also wore florescent make-up.
The 28-year-old Welsh singer performed tracks from her EP - which is released on March 10 - as well as a haunting Elliott Smith cover and songs from the previous three EPs of her ambitious, five-part series.
For the second half of the concert Charlotte was joined by the London Contemporary Voices choir, and during the finale of the show - which was named 'Entanglement' after the lead track from 'FOUR' - giant tentacles of flashing lights came out from the 28-year-old singer's dress and wrapped around the entire audience.
Fans and guests were painted with UV make-up and were given glowing accessories as they entered the event to create a "cartoon" atmosphere.
Speaking about the gig, Charlotte - who signed copies of 'FOUR' for fans afterwards - said: "It's like a cartoon, big and bright and colourful, but it's also a product of us pushing what we can do and pushing the boundaries when we're performing live."

ITV has confirmed a new series of 'Mr Selfridge'.
The hit period drama starring Jeremy Piven will return for a third series next year, with filming due to commence in April.
ITV's director of drama Steve November said in a statement: "We're delighted to commission a third series of 'Mr Selfridge'. It's been very pleasing to see how the audience have reacted to 'Mr Selfridge' and the vibrant and inspirational world the production team have created."
Kate Lewis, executive producer for ITV Studios, said: "We have some surprises in store for an audience in this third series. You only have to walk down Oxford St today to know that Selfridges Department Store continued to be successful, but for its founder, Harry Selfridge, things were very different. His story was a rollercoaster ride that ended rather tragically. We pick up Series 3 in 1919, the point at which his life really begins to unravel."
The second series of 'Mr Selfridge', which stars Jeremy as Selfridges founder Harry Selfridge, has continued to perform admirably in the ratings on Sunday nights.
The series is averaging 6.4 million viewers and topped BBC One rival 'The Musketeers' in the ratings on Sunday (02.03.14).

Reggie Yates is proud of his pal Marvin Humes' presenting success.
The TV star and Holly Willoughby were replaced by the JLS singer and Emma Willis as the new co-hosts of 'The Voice' this year, and Reggie insists he didn't need to offer Marvin advice because his friend is deserving of the job and has a bright future as a presenter.
Asked how he feels about new presenting duo, Reggie exclusively told BANG Showbiz: "I think it's great. I know Emma very well - I've known her for years, we did a show together ages ago. I think she does an incredible job on 'Big Brother' so I'm sure she's doing great on this.
"Marvin is genuinely one of the nicest people alive, there's not a bad bone in his body, he's such a nice guy, so chilled out. Its amazing to see him get this opportunity, he deserves it.
"I didn't give him advice that's patronising, that's rude. I just said, 'Congrats and good luck!' I knew he would do well. It goes without saying. There's a lot of people who don't need a pat on the back because they deserve it. I'm just really happy for him."
However, Reggie admitted he hadn't watched a single episode of the BBC One show this series because he's been away filming his new documentary series 'Extreme South Africa', and preferred to spend his one evening off catching up with Marvin and his wife Rochelle rather than glued to the TV.
He said: "I've not been in the country! The one night that I was here and I was able to watch it I was at Marvin's house for dinner ... myself, my girlfriend, Marvin and Rochelle all had dinner at their house and it was lovely.
"Roch cooked. The telly wasn't on, we were too busy chatting! But loads of my mates are talking about it so I'm going to iPlayer it."
Reggie was joined by singer Dannii Minogue, interior designer Kelly Hoppen and musician turned cheese-maker Alex James in central London today (06.03.14) at the launch of eBay's new features to create an inspiring and more personalised shopping experience.
eBay users in the UK can now enjoy the global commerce site's new features including creating your own collections, following others and discovering the very best collections.
Follow the Curators eBay Collections at www.ebay.co.uk/today.