The actress will star as Emmett Till's grandmother Alma Carthan in the upcoming movie, which centres on the story of Till's mother and her fight for justice.
Danielle Deadwyler has been cast as Mamie Till-Mobley, who seeks justice for her son after he's killed by a white mob.
Whoopi is also producing the project alongside Keith Beauchamp, Barbara Broccoli, Thomas K. Levine, Michael JP Reilly and Frederick Zollo.
The film is being directed and written by Chinonye Chukwu, and production work is poised to start later this year.
Whoopi told Variety, "We have waited a very long time to bring this historically necessary important film to people. And as we watch the repression of American History when it comes to people of colour it makes it even that more important. I couldn't be with better people: Fred, Barbara, Chinonye, Keith, Michael and Danielle."
It's not the only onscreen project about Emmett Till.
Jay-Z and Will Smith also join forces to produce a stirring mini-series called "Women of the Movement" about the 1955 incident. The series was originally set to air on HBO but has since moved to ABC and received the go-ahead from the bosses at the Alphabet.
In 2019, Taraji P. Henson additionally confirmed a feature film where she's set to play Mamie Till-Mobley.
"I can already tell that the hardest one (film) I'll ever do is playing Emmett Till's mother, and I haven't even finished reading the script yet," she said back then. "John Singleton wrote it, and it's just brutal. Every page is making me ugly-face cry."