Carey Mulligan feels old.

The 'An Education' actress - who is dating actor Shia LaBeouf - admits her work and life experiences make her seem much older than her 24 years, though she is still a teenager at heart.

She said: "I think I feel older. You meet a lot of people much older, one of my closest friends in an actor called Denis Lawson who is in his fifties. I met him when I was 20 on 'Bleak House' and we are bonded by an experience and so yes, in some ways I feel older but in some ways I feel like a 13 year old.

"But also, I've been working, I have a career, I've bought my own flat, I have a mortgage - so sometimes I feel annoyingly grown up and I don't want to be but most of the time I feel 12."

The 'Public Enemies' actress also admitted she won't carry on acting forever.

She said: "I have always wanted to keep going for as long as I want to but then I will stop if I get bored or if I get frustrated or tired - but I don't feel it."