Blake Lively and Ryan Reynolds are ''rivals''.

The celebrity duo welcomed their first child, James, four months ago and Blake, 27, has revealed they are squabbling over their daughter's first word.

Speaking on 'The Tonight Show with Jimmy Fallon', she said: ''We're total rivals. I hear [Ryan] all the time, 'Da-da, da-da,' and then I walk in the room and he's like, 'Ma-ma.' And I'm like, 'How dare you do that?' ... The word 'Da-da' is banned in our house.

''She has to say 'ma-ma' first. I do everything! He does nothing!''

Blake recently confessed Ryan is such a hands-on dad that he constantly smells ''like poop''.

She said: ''He just smells like poop...he's in full diaper duty. He likes the big ones, because they're easier, so her diapers are like up to her chest.''

What's more, the former 'Gossip Girl' star revealed her daughter already looks a lot like her famous dad.

She joked: ''I think she looks like her daddy. I want a maternity test!''

What's more, Blake said nothing about her family life has been a ''sacrifice''.

She explained: ''Being a parent is both exhausting and all-consuming but it is the greatest gift in the world. I never feel as though I am giving up anything being a young mother - there's no sacrifice. I feel like I've won the lottery. The only thing I am giving up is sleep.''