Alec Baldwin says trying to keep up with his wife's pregnancy cravings is difficult.

The 54-year-old actor's spouse Hilaria Thomas is expecting their first baby later this year and while she can't quite decide what foods she is craving, Alec - who already has daughter Ireland, 17, from his marriage to Kim Basinger, has taken matters into his own hands.

He told chat show host David Letterman: ''Being around a woman when she's pregnant and I'm older now -- quite a bit older, actually -- it's just really ... it's amazing.

''Like my wife, the pregnant woman, the hormonally-charged woman if you will - uh, it's thrilling. It's a thrilling thing to observe.

''She's been super fit her whole life and nutritionally very conscious. I'll say to her, 'You want to eat smart and keep up your nutritional values, but you gotta eat, you're having a baby'. I'll go, 'Do you want me to go get you some pineapple?' And she'll be like, 'I don't know.'

''There's a container of pineapple that will probably serve four people. I put it on the counter [and] I go, 'If you want some pineapple, here it is'.

''I go to the other room, I plug my phone in to charge it [and] sure enough I walk back -- three quarters of the pineapple is gone and she's like, 'I was very hungry.'''

Alec also revealed Hilaria has been quite vocal about all symptoms of her pregnancy, including her constant need for bathroom breaks.

He said: ''My wife will be announcing, 'I have to pee every five minutes, I can't believe it!' Then I'm like, 'Well, we have four bathrooms in the apartment, so you're covered. We got a bathroom in every quadrant of the house at the ready, clean and freshly papered and everything good to go'.

''And then the next day she's like, 'I don't have to pee at all today. Something's wrong!' I'm getting whiplash here: pee, no pee...''