Folks on the set of Alias figured Jennifer Garner
had just had a few carbs too many. "She likes to eat," says a source. "Girl has a bagel, gets a pooch and—poof!—everyone thinks she's pregnant." This time, it seems, everyone was right. Nine months after Garner, 33, and Ben Affleck
, 32, began dating, sources say the couple are three months into a pregnancy. But don't expect any official statements of joy. In contrast to his very public romance with Jennifer Lopez
, the actor has kept his relationship with Garner private. They have spent their together time quietly hanging out in the Brentwood, Calif., neighborhood where they both live: grocery shopping, getting coffee at Starbucks, renting movies at Blockbuster and, oh yes, getting engaged. In early May a close friend spread the news that the two were planning to wed, to the delight of Garner's parents. "They had their fingers crossed," a Garner pal told PEOPLE. "They really love Ben." Soon after, she was sporting a diamond eternity band, although a wedding ceremony would have to be scheduled around work: Garner is already in Vancouver for the two-month shoot of the romantic comedy Catch and Release
. Her pregnancy, says a rep for the film, would "absolutely not cause any recasting." And what about Sydney Bristow, the action hero she plays on Alias? "I'm sure [executive producer] J.J. Abrams is glad he did that episode where Sydney's eggs were harvested," says a source. Back in Brentwood, Garner strolled into the baby shop Wonderland on May 2 and later sent an assistant to pick up a $66 stroller blanket in off-white. In Affleck's hometown of Boston, meanwhile, his mom, Chris, "would like nothing more than to have another grandchild," says a source. "She will be thrilled."
Karen S. Schneider. Tom Cunneff, Kwala Mandel, Brenda Rodriguez and Pamela Warrick in Los Angeles, Amy Longsdorf in New York City and Rebecca Paley in Boston