Bradley Cooper didn't wear underwear when he met US President Barack Obama.
The 'Silver Linings Playbook' actor and his girlfriend, Suki Waterhouse, met the US premiere at a state dinner last week, but he says gaining weight for a new role left him with no room for boxer shorts.
Speaking to talk show host Ellen DeGeneres, he said: "I'm prepping for new movie and I'm trying to gain weight fast, I've gained about 15 pounds in four weeks and nothing fits me anymore. I wore the tuxedo I wore to the Golden Globes and I just sort of threw it in the bag and went to Washington D.C.
"I'm getting dressed, like, 10 minutes before I was supposed to go and literally the pants go up to like here [halfway up his thigh].
"So I had to go commando because there was no room at all. I did. I had to... So it was really great. And you have to walk up the stairs and it was a nightmare. But I made it through."
Bradley, 39, is nominated for Best Supporting Actor for his role in 'American Hustle' at the Oscars on March 2 - his second year nominated for the award in a row - and is having trouble deciding between taking his sister and his mother with him, so appealed to Ellen, the awards' host, for help.
He explained: "I'm trying to take more than one person. My sister's coming from North Carolina ... How can I [choose?]. Maybe they'll sit them at the top, maybe there's some seats at the top?"
Ellen initially sounded doubtful, but later added: "I'll see what I can do for you."

Miley Cyrus stuffed a fan's thong in her mouth while performing on Sunday night (16.12.14).
The 'Wrecking Ball' singer surprised the audience at her Bangerz Tour show in Tacoma, North West US, when she spotted the red undergarment thrown by a member of the audience then proceeded to wrap it around her microphone and put it in her mouth.
A stunned audience member wrote on twitter: "OMFG SOMEONE JUST THREW THEIR THONG ON STAGE AND MILEY PUT IT IN HER MOUTH!!!! (sic)"
The singer's wild antics didn't stop there and at another point in the show she straddled one of her female backing dancers, and writhed around her, wearing a bright red fluffy waistcoat.
The Bangerz Tour kicked off in Vancouver, Canada on February 14, and features a number of surreal moments including Miley riding a giant hot dog, rubbing her crotch and sucking on a foam finger, as well as plenty of her signature moves - sticking out her tongue and Twerking, the butt-shaking dance move she popularised last year.
Despite the controversies, Miley, 21, has said she wants the show to be "educational" for children.
She said: "I hope people open their minds and they look at my tour as something that I do feel is educational for kids.
"Because I think a lot of people aren't exposed to art enough and that's something that I had to learn about ... they pretty much teach you everything in the world as black and white and I want my fans to walk away knowing more about the art that inspires me."

Mariah Carey's daughter will appear on her new album.
The 'You're Mine (Eternal)' singer - who has two-year-old twins Moroccan and Monroe with husband Nick Cannon - has been recording her little girl "ad libbing" after she began mimicking the lyrics from one of her new songs, and says the clips will feature on her forthcoming LP.
She said: "It's a song that I wrote with Bryan-Michael Cox and Jermaine Dupri. There's a part that Jermaine says on the song that [the kids] loved, and Monroe started to say it.
"I kept having to get my iPhone and record her. So I have all these different takes of her saying things, singing things. Then I'd be like, 'This is your new ad lib -- learn it!' I have to make it fun for her."
The 'Hero' hitmaker insists both of her children are already showing signs of musical talent.
She told People: "Well, they started singing and talking simultaneously. It's hard to explain. That sounds like a lie, but it's true. They're both so musical."
And Mariah claims she is a "tough" mother who won't let her kids watch non-educational programming - unless she is relaxing and watching TV with them.
She said: "Their favourite thing is, 'Lie down, Mommy.' Meaning, 'Lay with me and watch a movie.' Because otherwise they have to watch Your Baby Can Read or something educational. I'm a tough task-master like that."

'Downton Abbey's' Laura Carmichael thinks her character is the Carrie Bradshaw of the 1920s.
The actress, who plays Lady Edith Crawley in the period drama, imagines her to be like Sarah Jessica Parker's 'Sex And The City' alter ego, because she writes a column for a newspaper about women's issues, despite it not being mentioned often in the show.
Laura told vulture.com: "I do love to think of her in my head as Carrie Bradshaw of the 20s. She's got a column on being a modern woman. Probably far less racy."
Although Edith's work isn't mentioned much on the show, it is important to Laura that it remains a part of the character.
She explained: "Her writing was still going on this season, and I kept checking with the producers to make sure of it. She would submit an article monthly to the newspaper, and it would have been this casual column. It was pretty common of women of her status."
Lady Edith has recently been left heartbroken in the show after falling for editor Michael Gregson, who disappeared after she found out she was pregnant.
When asked if the tone of her writing would have changed in her newspaper columns, Laura joked: "Can you imagine? 'I couldn't help but wonder... where has he gone?' It writes itself."
Laura says Lady Edith chooses what she wants rather than what is expected of her and she is proud of her character
She added: "I love that Edith has become very brave. She's forced to along her journey, being left at the altar and such. I think she would have been the most traditional of all the daughters.
"In the end, life was harder on her and it falls on her to become a professional woman and write for a newspaper and find a different path for herself. That's really cool."

Tori Spelling has claimed Farrah Fawcett has sent her a message from beyond the grave.
The 40-year-old actress was seeing TV psychic John Edward in the hope of contacting her late father Aaron Spelling - who died in 2006 aged 83 - but was instead contacted by the late actress, who starred in the producer's show 'Charlie's Angels'.
Tori said: "Farrah Fawcett came through in my reading loud and clear. It was real."
Tori used to live near Farrah - who died of cancer aged 62 in 2009 -
and says her former neighbour wanted her to pass a message on to her former partner Ryan O'Neal and their son Redmond about "what she was doing and what was going on."
The reality TV star - who has children Liam, six, Stella, five, Hattie, two, and Finn, 17 months, with husband Dean McDermott - later wrote a letter to Ryan about her psychic encounter, but has not heard back from the 72-year-old actor.
She added to 'Access Hollywood': "She gave very specific details about things to tell them.
"I haven't heard from Ryan. I am hoping he understood what I was trying to say and doesn't think I'm some loony."

Lisa Marie Presley is a "scary" mother.
The 46-year-old singer is very protective of her kids, Riley, 24, and 21-year-old Benjamin - who she had with first husband Danny Keough - and five-year-old twins Harper and Finley, who she has with spouse Michael Lockwood.
Speaking on 'Oprah: Where Are They Now?' she said: "I'm very, very much a very strong and intense lioness mother. Very scary, intense lioness mother."
Lisa Marie admits she is so protective, her older children used to keep things from her.
She added: "If something happened to them or someone was bullying or doing something, they knew that I would be very proactive in dealing with it, so they wouldn't tell me a lot. So I'm very, very protective number one. Also, [I] want to be their friend and protect them, but also get them to learn how to live in the world that we're living in."
Lisa Marie also spoke of how she has taught her kids they will be "loved" because of their famous grandfather, late singing legend Elvis Presley.
She added: "They kind of know, because they heard music and stuff and they've gotten the idea. I just say he was a very special person who sang and he touched a lot of people in the world and, and people loved him and they're going to love you because of him. And they kind of understand that."

Britain's Prince William has called for all the ivory in Buckingham Palace to be destroyed.
The Duke of Cambridge recently launched the charity United for Wildlife - which aims to end the illegal wildlife trade - and the second-in-line to the throne now revealed that he wants all of the ivory at the royal residence to be removed to encourage people to take up the fight against poaching.
The royal collection is comprised of approximately 1,200 items spanning over hundreds of years, including a throne from India, and William hopes if the British royal family set an example it will persuade other heads of state to follow suit.
Leading primatologist Jane Goodall told the Independent on Sunday newspaper that William - whose wife is Duchess Catherine - had personally informed her he would "like to see all the ivory owned by Buckingham Palace destroyed".
The prince's wish comes just days after he attended the world's largest ever conference on the issue at London's Zoological Society which called for an end to the £12 billion illegal trade in animals and their body parts. The campaign was highly successful last year with at least 45 tons of ivory seized in what's believed to have been the largest haul in 250 years.
William's father Prince Charles has also been encouraging the move and is believed to have asked for ivory items at Clarence House and his Highgrove property to be put out of sight over the last few years but experts say William's plans for destruction will send a powerful message to the world.
William, 31, attracted criticism ahead of his speech at United for Wildlife when he photographed hunting for boar in Spain with his brother Prince Harry, 29.

David Bowie's producer claims there are "astounding" tracks left over from recording sessions for the singer's 2013 album, 'The Next Day'.
Tony Visconti spoke at the Music Producers Guild Awards on Friday (14.02.14), where he collected Bowie's innovation honour on the artist's behalf, and said "two or three" unreleased tracks could be released.
According to the BBC, he said he and Bowie were "very excited" by the reaction to the comeback album, which was nominated for the Mercury Music Prize.
He said: "We were very excited with the reaction. Honestly I was in a daze for the first week, because keeping a secret for two years took quite a lot of lying. I almost started believing my own stories!
"No one believed that David Bowie was going to make another album and so the timing was perfect, because everyone kind of gave up on him."
When rumours began circulating that the 67-year-old star was in bad health and planning to retire, Tony says he was "laughing" because he was fine.
He added: I'm in the studio with a very healthy man who has no problem writing songs, he wrote easily 30 songs for that album."
David Bowie is nominated for two BRIT Awards this weekend for Best Album for 'The Next Day' and Best Male Solo Artist, but he will reportedly not be attending the event on Wednesday (19.02.14) at London's O2 Arena.

George Michael doesn't "understand" why he has had to edit his new single.
The 50-year-old singer has digitally-removed the audience noises from his latest track 'Let Her Down Easy' - which was recorded during his 'Symphonica' world tour of 2011-12 - because of rules that would have prevented it from being played on radio, but he is unsure why the move was necessary.
He tweeted: "Good Morning campers! Just out of intrest, Let her down easy is indeed a live vocal, but radio these days wont any live or live sounding...
"sorry i meant radio wont PLAY any live or live sounding tracks on the radio on their playlists anyore, so we had to go in and ...
"get rid of all audience sounds off the track..I know i dont understand it either (sic)"
George previously went to number one with two live duets, in 1991 with Sir Elton John on 'Don't Let The Sun Go Down On Me' and two years later with Queen on 'Somebody To Love', and he is grateful the rules didn't apply when he released those songs as they would never have been so successful.
He added: "all i can thank god for is that it's a recent development because id have lost on two number one's, with Elton and queen! Anyway, just thought you'd like to have that cleared up (sic)"
George's latest record, also named 'Symphonica', will be released on March 17.

John Legend wants to become a coach on 'The Voice'.
The 'All Of Me' singer has revealed he was in talks to join the BBC talent show when it first started in 2012 but instead ended up joining 'Duets' in the US with Kelly Clarkson, Robin Thicke and Jennifer Nettles.
John exclusively told BANG Showbiz: "I did something like that ['The Voice'] in the States with 'Duets' and I was actually in discussion with 'The Voice' UK a few years ago but it didn't work out.
"I don't know all the details, but I'm open to it if the time is right. I think it would be fun."
During the first series of 'The Voice', which saw Tom Jones, will.i.am, Jessie J and The Script's Danny O'Donoghue mentor acts, contestant Jaz Ellington covered John's hit song 'Ordinary People', which shot up the charts as a result of his performance.
John, 35, said: "I love it [when people cover my songs], I think it's great.
"It's good for me as an artist, it makes people say, 'Oh, I wanna hear the original song', and as a songwriter it's an honour to know other singers love your songs."
The star admits he doesn't often watch talent shows in the US or the UK but enjoys mentoring new talent and would still like to be on a judging panel in the future.
He added: "I enjoy being a part of them and mentoring and performing, but I don't really enjoy watching them."
John's album 'Love in the Future' and single 'All of Me' are out now on G.O.O.D/Columbia.

Suzanne Shaw had "snot bubbles" after being axed from 'Dancing on Ice' last night.
The former Hear'Say singer became the latest celebrity to be eliminated from the all-stars series of the ITV competition last night (16.02.14) and she admits she was overcome with emotion when the news was delivered.
Appearing on ITV's 'This Morning' earlier today (17.02.14), she said: "Last night I was really like, 'It is what it is and that's fine' ... but I actually burst into tears and I was going to Matt, with snot bubbles, 'Please just help me out right now, I need to get myself sorted!' "
Suzanne, 32, was in the skate-off with Kyran Bracken last night - despite earning her highest score of the series so far - and she admits she is "gutted" to lose her place in the competitive final series of 'Dancing on Ice'.
She lamented: "It was really difficult and it's a bitter pill to take when you feel like you've put everything into it, and the aches and pains that you go through. And I've got to be honest, I'm gutted. But at the end of the day, it is what it is."
Suzanne's skating partner Matt Evers also revealed that the petite blonde suffered a scary injury while rehearsing for last night's routine.
He explained: "In dress rehearsals she actually smacked her head when doing that move where she goes back over on top of herself. And together with the physio team, we were a little bit concerned, was she going to be all right for the show?"

Charlie Brooks will make a fleeting return to 'EastEnders'. The actress - who plays Janine Butcher - was last seen in the soap on Christmas Day (25.12.13) when she was arrested for the murder of her husband Michael Moon (Steve John Shepard), but she'l...