Hudson turned heads in a metallic, one-shoulder Stella McCartney gown, and accessorized with a silver clutch and diamond earrings.
"Marshall ready! #PremiereTime #NYC #OutOct13 @marshall movie," she captioned a photo of her look on Instagram.
Hudson told E! News at the event that her 6-year-old son, Bingham, was the one who gave her the dramatic haircut.
She shaved her head for a role in the upcoming movie "Sisters," which is directed by Sia.
"Bing actually cut it. I thought for him to be a part of it wouldn't feel so shocking," the star said. "My kids really didn't care."
Hudson previously said in an interview with Entertainment Tonight that she "copied" 13-year-old son Ryder's buzz cut.
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"I copied Ryder," the star shared. "Ryder had it way before. Ryder's been buzzing his head for a long time."
"Ryder's like, 'Mom, you're cramping my style,'" she said. "But when I did it, he was like, 'Oh my God, we actually...' It was the first time he could even see that we looked, you know, that he looked like his mommy.'"
Hudson shares Ryder with ex-husband Chris Robinson and Bingham with ex-partner Matthew Bellamy.
"Marshall" follows the life of late Supreme Court Justice Thurgood Marshall (Boseman), and opens in theaters Oct. 13.
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