"I thought I'd drop by to let you all in on some exciting news -- Honor is going to be a Big Sister!" the actress wrote. "Cash and I are thrilled and wanted to share the news directly with you so you didn't hear about it somewhere else."
Continued Alba, "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."
Though the star played coy last fall when UsMagazine.com asked if they were looking to add on to their brood -- "We are enjoying [Honor]," she said -- she couldn't help gushing when it came to her two-year-old daughter.