The 39-year-old actress walked her first red carpet since giving birth, attending the Tribeca Film Festival premiere of her new film,Disobedience, in New York City on Tuesday. McAdams could not have looked more stunning in a showstopping semi-sheer floral gown with ruffled detailing and deep V neckline.
The new mom, who reportedly welcomed a baby boy with boyfriend Jamie Linden, swept her brunette locks to the side in a chic chignon and accessorized her look with minimal jewelry and natural makeup. Adams was all smiles as she posed for photos on the red carpet.
ET spoke with McAdams' Disobedience co-star, Rachel Weisz, at the premiere, where she opened up about her and McAdams' pregnancies.
"I think that it was very powerful love, very powerful love making," she joked. "I don't know, it's a mystery!"
"Chemistry is a strange thing. It either happens or it doesn't, it's kind of alchemy," she said of her connection to McAdams in the film, which tells the story of a forbidden love between two women. "Rachel's very easy to fall in love with. She's magnetic, she's intelligent, she's beautiful. She's got depth, she's got soul."
"I don't know, something just happened with the story that just affected us both really deeply, and I think it happened," she continued. "You can't force it."
Disobedience hits theaters on Friday. See more on Weisz in the video below.