The My Week with Marilyn star, who received a nod for 'Best Actress' for her portrayal of Marilyn Monroe, confessed that she was too busy to watch the announcement on the day of the nominations.
"I was with friends and it had slipped my mind, which is something so great about having a kid, is that you get really absorbed," Williams said in an interview with The Today Show.
"Especially mornings, because you've got to get out the door, you've got to make breakfast, you've got to get the snow suit on, you've got to get everyone in the car - I was carpooling."
Williams previously said her nomination is a testament to the legacy of Monroe.
The Academy Awards will be held on Sunday, February 26 at Hollywood's Kodak Theatre.
Watch Michelle Williams talk about her Academy Award nomination below: