The Fantastic Four beauty, 29, gave birth to daughter Honor in June 2008 and now the couple is preparing for a new addition to its family.
Announcing the news via her Facebook.com page on Wednesday (16Feb11), she writes: "It's been a while since I've been on FB & I thought I'd drop by to let you all in on some exciting news > Honor is going to be a Big Sister!
"Cash and I are thrilled and wanted to share the news directly with you so you didn't hear about it somewhere else. I appreciated all of the love and support you all gave me during my first pregnancy and will definitely appreciate it again this time around. Have a great day! Jess."
And Warren has taken to his Twitter.com page to express his delight: "@jessicaalba (and I) are beyond excited about the news! Honor is going to be a great big sister. Thank you all for the wonderful messages!!"
Alba wed film producer Warren in May 2008.