But life imitated art Monday night as she walked the red carpet at the movie's Manhattan premiere, where Rudolph, 36, wore a flowing Yigal Azrouël dress with a thin belt that accentuated her very real bump. Due "around November," according to her rep, Rudolph told PEOPLE that getting decked out for a red carpet these days is "not fun."
"I do my best. This is super dressed up," she said. Indicating her gown, she asked, "Isn't it beautiful?"
This is Rudolph's second pregnancy with her partner, director Paul Thomas Anderson – daughter, Pearl is 3. "I was sick as a dog for the first trimester," said Rudolph. But now I'm totally fine."
Krasinski CostarsAway We Go director Sam Mendes joked that Rudolph had gone beyond the call of duty for the sake of the film, which tells the story of an expectant couple (John Krasinski costars) who travel far and wide to find the perfect place to raise the child.
"It's an amazing act of selflessness that Maya Rudolph agreed to become pregnant a second time to promote this movie," quipped Mendes.
At the film's grandly eccentric Jane Street Hotel after-party, Mendes said that already being a mother prepared Rudolph for the role of a pregnant mom: "You remember how it feels, how to move, walk. You know how people react to you."
Added Mendes, who has a son, Joe, with his wife, Kate Winslet, "Being a parent softens you. It makes you fascinated in other parents. You're always looking at other people to see if they have it a little bit more right than you have."