Ben and Jen Hunt for a House

Their family is about to grow, and now Jennifer Garner and Ben Affleck may be in the market for roomier digs.

“I guess they are looking for a bigger place now,” pal Kevin Smith told PEOPLE at a the Maxim magazine party on Saturday in San Diego where he attended Comic-Con.

The director-actor, who is a longtime friend of Affleck and starred with Garner in 2006’s Catch and Release, also revealed how he learned the news that the couple – who are parents to daughter Violet, 2 – are expecting again.

“I saw him last week. Ben came over to watch my movie (Zack and Miri Make a Porno) at the house, and he told me, ‘We’re having another baby,’” recalls Smith.

He added that parenthood comes naturally to both stars. “[Jen] is such a Martha Stewart type. She is a perfect mom,” he says. “And [Ben] is a great dad, which I found not that surprising, but it’s a side of him that I never thought about before he became a dad. He’s a great father. He loves that kid of his.”