The show's fourth season is set to begin filming in February, with new episodes premiering this summer.
Kardashian will play Nikki, Fred's new love interest, who partners with his ex, Stacy, in a new business venture, a synopsis said. Ben Feldman plays Fred and April Bowlby plays Stacy.
"I'm ecstatic to welcome Kim to the 'Diva' family," the show's creator and executive producer Josh Berman said in a statement.
"In discussing the role of Nikki with her, I'm blown away by her smarts, sense of humor, and passion. This series is all about reinvention and I'm so excited to see Kim 'reinvented' in the world of 'Drop Dead Diva.'"