'Cider?" Dom-inic Cooper asks as I enter the room on a dull Monday morning in London. It seems a little early for that kind of behaviour but the question itself is surprising. From all I've read, Cooper has never come across as a latter-day Oliver Reed, hitting the bottle from morning until night.
Instead, he's always seemed like more of a Colin Firth-type figure, unfailingly nice, pleasant and accommodating; the kind of guy who makes girls drift into a daydream at the mere mention of his name.
It turns out the cider he's offering is merely some posh apple juice and so Cooper's reputation remains intact.
It's probably just as well, as there would be one or two of the film industry's major players having a heart attack if Cooper was to start hitting the bottle. There's a lot riding on him these days.
The past few years have seen the 31-year-old Londoner move from being a relatively unknown theatre actor to the bright young thing of British cinema.
He's received plaudits for his acting ability; he adorns the walls of teenage girls' bedrooms throughout the world, and has a secret place in the hearts of their mothers.
Ever since Alan Bennett's The History Boys was released in 2006, using the same cast as the stage play, his career has been on the kind of upward trajectory that previous British charmers such as Orlando Bloom and Jude Law must have wished they could have harnessed more effectively.
He had a role in The Escapist alongside Joseph Fiennes and Brian Cox, and then starred in Mamma Mia!, the biggest grossing film musical of all-time.
He followed that with the role of prime minster-in-waiting, Charles Grey, who falls for Keira Knightley's charms in The Duchess.
He's been taught some harsh lessons over those years while his stock has continued to rise.
In a tabloid interview last year, his honesty landed him in some difficulty as he revealed that his father, who separated from his mother when he was a child, had fathered a child with another woman while he was still married to Cooper's mother. He revealed that his father had drunkenly told him the news at his older brother's wedding.
I ask if he regrets the honesty he showed in that interview in particular.
"Yeah, absolutely," he replies with an almost disbelieving laugh. "I did that without any knowledge of how anything worked at all, and perhaps I should have been led a bit more wisely by people who did know.
"Still, I don't think there's any point in being in interviews without being open and honest, but I think you have to protect people that you care about and I didn't quite realise the damage or how things can be manipulated to be seen or said in a different way."
As well as his family revelations, Cooper was also remarkably forthright about his private life and the end of his 12-year relationship with Joanna Carolan, PA to the late Harold Pinter, and the beginning of his romance with Mamma Mia! co-star Amanda Seyfried -- events which seemed to occur simultaneously.
"I literally said those things once and what amazes me is that they constantly come back, and even if you don't mention them they are referred to. That is quite sad and I should have known better, but I didn't.
"I was actually tricked into saying stuff as well. It was quite amazing. I was like, 'F*** me. Will you really go to those lengths to get that information?' You have no control, but you learn that you are part of a system and we all crave a certain type of knowledge with the whole magazine and celebrity culture -- learning more about people's lives and we start to lack interest in their talents. That's quite disturbing for me, but that's what people seem to want to know about."
His fame may have come at a price, but Cooper and Seyfried have all the credentials to become one of Hollywood's golden couples. He's adamant, however, that they have no enthusiasm to lead any kind of celebrity lifestyle.
"No, absolutely not. And she couldn't be more different from that either. It doesn't interest us in any way. And we live in different countries."
That they do. While Cooper has remained in London, close to his mother in Greenwich, Seyfried is in the US, where her career is rising just as quickly as his.
"It's really hard," Cooper says, "but we've been really good with it just making sure that it doesn't go too long [without seeing each other]. Air fares are quite a lot. Work makes you travel a lot anyway and we've just managed to make sure that we're never more than two weeks away from one another at any time for the past couple of years, so that's been really important."
Cooper's latest film was made just a few miles from where he was raised. Based on a memoir by journalist Lynn Barber, and adapted for the screen by Nick Hornby, An Education is essentially a coming-of-age story of a young girl growing up in a dreary London suburb in the Sixties.
Carey Mulligan plays Jenny, an intelligent teenager with dreams of Paris and a life far away from hers. She meets an attractive and seductive older man, David (Peter Sarsgaard), who shows her the world she has been imagining. Cooper -- who only got the role the day before filming began after Orlando Bloom pulled out -- plays Danny, David's best friend, and a man with impeccable taste in art and music and a brilliantly ditzy blonde girlfriend (Rosamund Pike).
It's a remarkable story and I imagine the cast and crew will be making several trips to the stage at next year's Oscar ceremony. Cooper understands the seductive power a glamorous world can have on a young, wide-eyed observer.
"I feel very guilty now when a big press junket happens and you can be flown out on a private jet to go and sit on a yacht on an island in the middle of nowhere and you think 'this is f***ing amazing'. You get completely sucked into it and it's actually disgusting.
"It's over the top and lavish and rancid, but there's something that makes you go, 'wow'. You get kind of addicted. You think that is your life. That's the mistake to make. To be drawn into it and believe that it has any connection or comparison to who you are or what your life is. That's why it's so wonderful to go back and hang out with your mates from primary school in your local dustpit."
Those dustpits tend to be in London where, when he's not jetting across the world to see his girlfriend, he shares a house with Gavin and Stacey star James Corden. I wonder, has he had to adjust his life much now that he is something of a celebrity?
"No, I haven't adjusted in any way. I don't know if I should have," he laughs.
He's seen the effect it's had on Corden, however, thanks to his portrayal of everyman Smithy in the hit TV show.
"When I'm with him, people feel like he is very much a piece of public property. He's absolutely theirs. If he's having a crap day and doesn't feel like doing eight photos with people, they'll go 'you f***ing w***er' and be really horrible. I've seen it. I don't have anything like that. That, to me, is disturbing.
"You can play all kinds of roles and you can be all these different people in front of these new people that you meet all the time.
"You can kind of be something that you're not really, which is great. But ultimately to be around the people that know you so well, that have known you since you were five and don't listen to your bulls**t and can see you for who you are is so refreshing and brilliant and amusing, and that's what I love."
An Education is in cinemas on Friday