Jennifer said the recent speculation over her "baby bump" has made her giggle, saying , "It always makes me laugh when people say 'Is she?' Isn’t she?' It’s like eventually you will know, so just chill out for a minute!"
Jen also says she's more than prepared for the new addition, thanks to her daughter, Violet.
"Yeah, been through it,” Jennifer said. “It’s all good, it’s great. I’m really excited."
The child, whose sex Jennifer did not reveal, will be her second with husband Ben Affleck.
Garner and Affleck, both 36, married in June 2005. They have one daughter – Violet, who was born in December 2005.