Alec Baldwin's pregnant wife Hilaria has revealed she's carrying the actor's first son.

The Cooler star, who has a grown-up daughter, Ireland, from his marriage to Kim Basinger and a baby girl with his current wife, announced he was set to become a dad again with an Instagram.com post on New Year's Day (01Jan14) featuring a beach photo of his youngest daughter touching mum's exposed baby belly and the caption "2015 equals Mommy, Daddy, Carmen and a special guest".

Now Hilaria has told U.S. news show Extra she turned to gender-predictor tests to find out whether she was expecting a little boy or girl.

She says, "I think it's called Intelligender and that one said 'boy', but then we did the Heat Beat one and that said 'girl'. We also did the Chinese gender chart."

But Hilaria seems convinced it's a baby boy - she has posted a photo of a pair of blue booties on Instagram.com.

She adds, "We're really excited to have another baby! We definitely wanted Carmen to have a sibling near her age. She already has Ireland."

And the proud dad and daddy-to-be says, "I am very blessed, very blessed, we're having the baby and that's almost surreal to me."

The Baldwins' first son is expected this summer (15).