The prolific character actor, whose dozens of movies included an Oscar-nominated performance as a death row inmate in “The Green Mile” and box office hits including “Armageddon,” ‘’Planet of the Apes” and “Kung Fu Panda,” died Monday at age 54.

Duncan died at Cedars-Sinai Medical Center in Los Angeles, where he was being treated for a heart attack, said his fiancée, Omarosa Manigault.

By his mid-20s, he was in Los Angeles, where he looked for acting parts and became a bodyguard for Will Smith, Jamie Foxx and other stars. The murder of rapper Notorious B.I.G., for whom Duncan had been hired to protect before switching assignments, led him to quit his job and pursue acting full-time in 1997.