Keira Knightley cannot wait to have a drink after she gives birth.

The 29-year-old actress - who announced she was expecting in December - is desperate to lock her lips on a margarita cocktail when her pregnancy is over and she is particularly disappointed she won't be able to drink at the Academy Awards next week.

The brunette beauty - who is up for the Best Supporting Actress prize for her role in 'The Imitation Game' - said: ''I can't drink. I'm up for an Oscar and I can't drink at the Oscars.

''I went to the doctor - you have to get lots of doctor check-ups when you're pregnant - and she asked if I had any questions. And I said, 'Yes! When can I drink? Please! I just want a margarita.' ''

While Keira is unable to get her hands on any alcohol at the moment, her husband James Righton is more than making up for it but consuming all of her free drink himself.

Speaking on 'The Ellen DeGeneres Show', the 'Pirates of the Caribbean' actress added: ''My husband's having a great time. I'm eating for two and he's drinking for two.

''There's a lot of free champagne so he thinks because I'm not drinking the free champagne he has to. So all of it.''

Keira also revealed she has a fear of being peed on if she gives birth to a boy, but host Ellen was on hand to gift the star a changing table and a protective face mask to ensure her face stays urine-free.

She explained: ''Somebody said to me the other day the problem with boys is - sorry this is horrible - but when you're changing their nappies you can get the wee in your face.

''Yeah you see? I've got a lot of people nodding at me, but I never knew that before so it was terrifying.''