Rami Malek and Glenn Close also picked up prizes at the SAG Awards, which are seen as a possible indicator of Oscars success.
Black Panther has triumphed at the Screen Actors Guild Awards, picking up the ceremony's top prize for best film cast.
A superhero box-office smash featuring a predominantly black cast, the Marvel film has been hailed as a turning point in cinema and could make history if it repeats the win at the Oscars next month.
In a powerful acceptance speech alongside co-stars including Michael B Jordan, Lupita Nyong'o and Danai Gurira, Chadwick Boseman told how "all of us up here know what it's like to be told there is not a place for you to be featured even though you are young, gifted and black".
He also spoke about the film's effect on the industry, saying the cast knew they had "something special that we wanted to give the world".
Black Panther beat BlacKkKlansman, Crazy Rich Asians, Bohemian Rhapsody and A Star Is Born to win the prize at the SAG ceremony, which is seen as a possible indicator of how the Academy Awards could pan out.