The Grammy-winning singer will play the musician Sam Cooke in the NBC show, TV Guide reports.
He is expected to appear in the fourth episode of the show and will perform Cooke's classic 'Having A Party'.
News of Saadiq's casting comes shortly after Colbie Caillat signed up to play Lesley Gore in the drama.
Other musicians expected to be portrayed in upcoming episodes of the show include Frank Sinatra and Sammy Davis Jr.
The Playboy Club will premiere on September 19 on NBC.
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Watch a trailer for The Playboy Club below: