01/15/2012 AT 10:15 PM EST
It took a lot of time – and a few extra pounds
– for Michelle Williams
to make her on-screen transformation into Marilyn Monroe.
But Williams, 31, says she wasn't the only one immersed in the world of the iconic actress during the production of My Week with Marilyn
– especially around nighttime.
While accepting best-performance honors for her role in the movie at Sunday night's Golden Globe Awards
(live from the Beverly Hilton Hotel), Williams singled out her daughter from her relationship
with Heath Ledger
, 6-year-old Matilda Rose
, whom she praised for "suffering through six months of bedtime stories, where all the princesses were read aloud in a Marilyn Monroe-[sounding] voice."
On a more serious note, she said in her speech that her daughter's "bravery and exuberance is the example that I take with me in my work and in my life."
"I consider myself a mother first and an actress second," she said. "I want to say thank you [to Matilda] for sending me off to this job every day with a hug and a kiss."