The couple were joined by the actresses mum Sandra.
Rachel and Linden have been together since April 2016, but have kept their relationship and the new baby incredibly private.
The couple are yet to announce his actual birth date and name.
Earlier this year, reports surfaced that Rachel McAdams and longtime boyfriend Jamie Linden had welcomed their first child - a baby boy.
Now, the fist pictures of the new bub has surfaced.
Pictured in Los Angeles on Wednesday evening, the new parents looked smitten and doted on their little one.
Fans took to Twitter to share the adorable pics.
The couple were joined by the actresses mum Sandra.
Rachel and Linden have been together since April 2016, but have kept their relationship and the new baby incredibly private.
The couple are yet to announce his actual birth date and name.