Click on photos for more pictures of Drew pregnant.
The Charlie's Angels star, who was accompanied by her art consultant husband Will Kopelman, attended the annual Baby2Baby Gala in Los Angeles county on Saturday.
Drew turned heads in a floor-length grey dress, and judging by the beam on her face, the pretty blonde couldn't be happier.
The mother-of-one and her doting husband posed for pictures and looked more in love than ever, sharing a touching kiss on the red carpet.
Drew and Will, who married in June 2012, already have one daughter together, 13-month-old Olive.
The Hollywood star has made no secret of her desire to expand her family quickly, and a week ago confirmed her pregnancy.
"Last time I never commented on it and people just stalked me the entire time," Drew told PEOPLE. "So yes, it's happening, it's true. I tried to keep it a secret for as long as possible.
"Will is just thrilled — we both are. We just wanted so badly for Olive to have a sibling. In some ways, it's really for her. So congratulations, Olive!"
The 38-year-old actress also recalled the joyous moment when she found out she was pregnant again.
"I was overjoyed," said Drew. "It always feels so surreal, it's incredible. [I'm feeling] incredible, that, 'Here we go again' feeling. And blessed. Blessed."