"Dax is a gem – one of my closest friends," Poehler told PEOPLE at the comedy's premiere Wednesday night, as it kicked off the 7th annual Tribeca Film Festival in New York.
"A couple make-out scenes didn't make the [final cut], which I was upset about," noted the Saturday Night Live regular, 36.
But did Poehler's real-life husband, Will Arnett, grumble about her smooching with the sweet-faced Shepard – who plays her onscreen hubby? "Oh, they're good friends," she says. "He didn't mind."
The movie (which opens to the public Friday) costars Tina Fey as Kate, a single, white-collar careerist who hires the hard-partying, blue-collar Amy (Poehler) to serve as a surrogate mom once Kate learns she's not likely to conceive a child herself. Among the pregnant Amy's worst pre-natal habits: her unsatiable appetite for junk food.
Fey, herself the mother of a 2-year-old, could identify. "I had this thing for Entenmann's chocolate donuts," she recalls of when she was carrying her daughter, Alice.
"Somewhere during my pregnancy I gained something like nine pounds in two weeks and my doctor was like, 'You know what it might be? Are you drinking a lot of juice?' I was like, 'Yeah. That must be it.' " said the 30 Rock Emmy winner, 37. "I was eating like a box a day of Entenmann's donuts."
Trailer EnvyAlso attending the premiere were the film's Holland Taylor and Sigourney Weaver, as well as festival honchos Robert De Niro and his producing partner, Jane Rosenthal. And while Poehler and Shepard didn't make out on the red carpet, he did attend the big night for his movie with his girlfriend, Heroes star Kristen Bell.
He also joked that his dressing-room trailer on the Baby Mama set wasn't as large or well stocked as his costars'. "Mine was in the back of a truck where they keep all the lighting, lighting equipment and generators," he said.
Fey's trailer, meanwhile, was "Shangri-La on wheels," said Shepard. "They were pampered like no one's business. They had a lot of deep penetrating moisturizers, hair volumizers, cool drinks, air conditioning, assistants …"