Mekhi Phifer is an American actor. He portrayed Dr. Greg Pratt on NBC's long-running medical drama ER from 2002 to 2008, and had a co-starring role opposite rapper Eminem in the 2002 feature film 8 Mile. He was a recurring cast member on the Showtime drama House of Lies, and also starred as CIA officer Rex Matheson in Torchwood: Miracle Day. Phifer is also known for his appearance in the music video for "The Boy Is Mine" by Brandy and Monica.

Gregory Pratt, M.D. is a fictional character from the medical drama series ER, portrayed by Mekhi Phifer. He first appears as a recurring character towards the end of the eight season, becoming a main character from the start of the ninth season until the start of the fifteenth season.