Jessica Alba insists she will have no more children after she gives birth to her third child.

The 36-year-old actress had daughters Honor, nine, and Haven, six, - who she has with her husband Cash Warren - and she is pregnant with a boy, but the star is adamant she is ''done'' with having more children and has vowed not to expand her brood any more when she welcomes the new addition to the family next year.

Speaking about her family plans on 'Extra', the 'Sin City' star said: ''[I'm] done, done, done. Yeah, my friend was like, 'You are going to have another,' and I'm like, 'No, I'm not.' We're good -- three is good.''

Jessica's two children have taken the news they will be big sisters well, and they are ''proud'' they get to have a baby brother in the family.

Asked how Haven and Honor reacted to the news, she said: ''They are so proud that they get to be big sisters.''

And though Cash and Jessica have already experienced the late nights, teething, as well as the late-night cries and nappy changing, they are worried how a third child may impact on their ''family dynamic''.

The Honest Company co-founder said: ''Cash and I at night are like, 'What is it going to be like having another kid? What does that mean for our family dynamic?'''

And the couple - who have been married since 2008 - both have ''butterflies'' and are nervous about the pending arrival.

She added: ''We kind of both have butterflies.''

Jessica announced she was pregnant over the summer on social media, but the star has since revealed she does not feel ''glamorous at all'' when she is expecting a baby, and instead she feels like ''Humpty Dumpty slothing around''.

Speaking previously, the 'Fantastic Four' beauty said: ''I don't feel glamorous at all when I'm pregnant, so it's nice to kind of dress up and feel beautiful. I usually feel sort of like Humpty Dumpty, slothing around and hormonal, and nothing fits the same.''