It appears that the Mean Girls alum has finally become a mom, as reports claim the industry vet and her screenwriter boyfriend have welcomed a baby boy into the world.
The new doting parents were apparently cooing over their newborn son and how he is a "good sleeper", according to the online outlet. News breaking the news back in February, was photographed with the little one and her other half in pictures obtained by the Hollywood Pipeline.
McAdams hasn't commented on the news, and she made her last public appearance at the Toronto International Film Festival in September.
Rachel's pregnancy was first reported in February, when she missed the Los Angeles premiere of her new movie Game Night, with sources telling E!
The couple started dating in April 2016, but they kept their relationship a secret and down-low.
Linden is best known for penning the scripts for "We Are Marshall", "10 Years", and "Money Monster".
Rachel previously opened up about her plans for a family in 2009. She also added she was, "looking forward to it someday".
McAdams, meanwhile, has stayed mum on her personal life, though she has dated celebrities like her "Notebook" co-star Ryan Gosling, Josh Lucas and most recently actor Michael Sheen. She's a nurse and very nurturing and gentle.