Vera Farmiga is giggling as she recognises me on the red carpet. "I remember you," she says, as she catches her breath. "You're the one that asked about that scene." It was a reference to hours earlier when we had met in a Mayfair hotel suite, and I dared to ask about her love scene with George Clooney in Up in the Air.
In the drama, directed by Juno's Jason Reitman and based on the novel by Walter Kirn, the 36-year-old lies naked on a bed, with her pert bottom showing, while a topless George stretches out on the floor beside her.
The scene was shot just weeks after Vera gave birth to her son Fynn.
"I had shot this when I had six pounds more chunk on my behind," she reveals, bursting into laughter. "I did attempt to do the nude scene, but I think my bottom had become too large. I got to help choose my body double and I thought Jason did a good job in selecting someone who was pretty accurate."
The New Jersey-born actress plays confident businesswoman Alex, who not only seduces commitment-phobe commuter Ryan Bingham (Clooney), but plays him at his own game.
"It was challenging to play a woman who is very much like a man," she admits. Often, when a woman behaves in this way, it can be misinterpreted. I appreciated that equal balance of power.
"I also loved walking this tightrope of wanton unapologetic sexuality and femininity. I thought that was a challenge and a treat to tackle.
"It was difficult for me, and it was a fine line to tread, to have this softness and, in the end, she takes control of her sexuality. I really liked the male perspective on the heartbreak."
Farmiga met Reitman to discuss the role when she was in the throes of pregnancy, and thought she wouldn't be suitable as a mum- to-be.
"I thought I had no chance because I was in the 11th-hour of my pregnancy and I was bigger than Jason and George combined," she quipped.
"I'm a sucker for good old-fashioned romance, and the female roles in the Reitman films are always the smartest, wittiest and most intelligent female roles you get to read.
"I was hungry for where the woman can really go tete-a-tete with her male counterpart."
And she has only praise for her hunky co-star. "He's a dreamboat," she says. "He'll make anybody weak in the knees -- male or female.
"George was exactly the partner I needed, because I have never felt as insecure as I did coming into this role. I had just given birth to my first child two weeks before my first costume fitting, so I really needed an ally and he was wonderful."
She adds: "His sense of humour is sincerely the most attractive thing about him. It's just jokes, nothing but laughter and giggles. He's the consummate gentleman, extremely kind and loving."
Being in such close proximity to the Hollywood pin-up allowed Farmiga to observe the mania that surrounds him. "What was most amusing for me was to see the fanaticism that George attracts," she says. "That was overwhelming and so odd.
"No one ever knows who I am -- they always think I'm a producer on a film. Watching George have to deal with that -- he'll open a door and close it, and get a standing ovation, or he'll get one when he walks. He is so gallant and gracious."
Not many actresses get the opportunity to banter and tell off an esteemed actor such as Clooney, but Farmiga's co-star Anna Kendrick does in Up in the Air.
The softly-spoken star who, at 24, is half the age of Clooney, portrays Ryan's colleague, Natalie, who aims to bring a halt to his jet-setting ways with her cost-cutting measures.
"I'm normally so timid in real life that I get excited by my character getting to tell people off, and telling someone like George off was pretty awesome," she says, blushing.
Her on-screen rapport with Clooney has already won her numerous nominations, including a Golden Globe and Screen Actors Guild for best supporting actress -- both seen as precursors to the Oscars in February.
"Surreal is the right word," she says. "It's very strange for me to sit in my filthy, unwashed Prius, which I've had since I was 18, or in my room with my pile of laundry, and feel like there are people talking about Oscar buzz!
"It's strange because I feel like people who get talked about in that way are these kind of perfect human beings. You're supposed to be really polished and grown up to get Oscar buzz."
Kendrick, who became the second youngest Tony Award nominee and appears in the Twilight film series as Jessica Stanley, embraced the role, which had been written specially for her.
"This script is so beautiful and the most incredible thing about it is this girl, Natalie, never has a romantic interest," she explains.
"It's never about her sexuality; it's just about this character who happens to be female. She's completely her own and has issues and problems.
"It's a rare thing, this girl who's so intelligent and complicated, and her world doesn't revolve around a romantic storyline. You don't read scripts like that."
Natalie admits that she never thought she would get the role. "I was shocked beyond belief because I thought Jason hated me," she says.
"My audition was very strange and I think Jason was trying not to psych me out, by not showing any kind of enthusiasm, and I thought he hated me. Then, when I got the job, I was thrilled beyond words."
The Portland-born actress reveals she was "intimidated" at the prospect of filming the scenes with Clooney.
"I was so terrified, but he goes so out of his way to make people feel comfortable because people tend to get uncomfortable around him -- he is George Clooney. But he's amazing."
The Academy Award-winning actor, who's famous for playing pranks on his co-stars, was well-behaved on this set, says Kendrick.
"He didn't play any practical jokes," she states. "I think it's because Vera just had a baby and he knew I was terrified, so he didn't really want to pull any pranks."
Up in the Air is released on January 15