Jennifer Garner Will "Plump Up" After She Quits Breastfeeding

Credit: Steve Granitz/

Julia Roberts is eager for her Valentine's Day co-star Jennifer Garner to regain a few Alias-era curves.

"You are quite slim," Roberts, 42, joked to Garner at the Beverly Hills press conference for their romantic comedy, in theaters Feb. 12.

"I just finished nursing," replied Garner, 37 -- who welcomed daughter Seraphina in January 2009. "I'll soon plump up again."

Quipped Roberts, "We'll stay tuned for that."

Garner also poked fun about falling in love with her husband of four years, Ben Affleck. 37.

"Somewhere around the second kid I thought, 'This is really turning into something!'" she said.

The busy parents (who are also raising Violet, 4) squeeze in romantic moments whenever they can, Garner said.

"You change the definition of romance," she said. "Romance is romance, but in addition, romance can just be breakfast over the tops of heads and just getting through the day. You've got to find a way make that romantic."