Rachel McAdams says motherhood is the "greatest" experience of her life. The 40-year-old actress and new mother discussed parenthood in an interview with The Sunday Times after welcoming a baby boy with her partner, screenwriter Jamie Linden. "It's the greatest thing that's ever happened to me, hands down," she told the publication. "[People say] your life is not your own anymore, but I had 39 years of me, I was sick of me, I was so happy to put the focus on some other person." McAdams gave birth to her son in April and is keeping details about the infant, including his name, private. She said she has no regrets about waiting "a long time" to become a mother. "It's just how it happened," the star said. "And I didn't want to do it before it was the right time." "The Notebook" star confirmed she is open to having more children in the future. "I think there is definitely room for more," she said. McAdams and Linden were first linked in April 2016 and have kept their relationship largely out of the spotlight. The couple were spotted walking with their baby boy in April after E! News reported McAdams' pregnancy in February. In addition to "The Notebook," McAdams is known for such films as "Mean Girls," "Spotlight" and "Doctor Strange." She also played Ani Bezzerides in Season 2 of the HBO series "True Detective."