The performer, 34, will play Magenta, the maid at Dr. Frank-N-Furter's estate and sister of Riff Raff. Patricia Quinn portrayed the character in the 1975 cult film.
Milian joins a cast that already includes Laverne Cox as Frank-N-Furter, Victoria Justice as Janet, Ryan McCarten as Brad, Reeve Carney as Riff Raff, Adam Lambert as Eddie and Tim Curry as the Criminologist Narrator.
Milian rose to fame as a singer with such tunes as the 2004 hit "Dip It Low." She can be seen on Fox's sitcom Grandfathered and E!'s unscripted series Christina Milian Turned Up.
Rocky Horror, a two-hour taped production, is set to air in the fall on Fox. It follows the network's recent musical production Grease: Live, which was a ratings success.
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