Oscar-nominated actor Michael Clarke Duncan died yesterday morning at Cedars-Sinai Medical Center in Los Angeles, where he was being treated for a heart attack, said his fiancée, Omarosa Manigault. Duncan was 54. The muscular, 6-foot-4 Duncan, a former bodyguard who turned to acting in his 30s, “suffered a myocardial infarction on July 13th and never fully recovered,” Manigault said in a statement. The Chicago native rose to fame playing a hulking death row inmate with a special psychic gift in the 1999 film, adapted from the novel by Stephen King. The role, which cast him opposite Tom Hanks, earned him Academy Award and Golden Globe nominations. Duncan parlayed his considerable size into a career as a Hollywood security guard, working for the likes of Will Smith and the rapper Notorious B.I.G. His first movie role came in 1998’s “Armageddon” with Bruce Willis; Willis later helped him land the “Green Mile” gig. Among Clarke’s television credits were “The Apprentice,” “The Finder,” “Two and a Half Men” and “The Suite Life of Zack and Cody.”