Michael Clarke Duncan was one big, irresistible jumble of contradictions.

His presence was formidable, even intimidating: The former bodyguard had a muscular, 6-foot-4 frame, but it was topped by the brightest of megawatt smiles.

His gravelly baritone was well-suited to everything from animated films to action spectacles, but no matter the role, a warmth and a sweetness was always evident underneath.

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. And although he only turned to acting in his 30s, it's clear from the outpouring of prayers and remembrances he received across the Hollywood and sports worlds that his gentle-giant persona made him much-loved during that relatively brief time.

Duncan died at Cedars-Sinai Medical Center in Los Angeles, where he was being treated for a heart attack, said his fiancée, reality TV personality Rev. Omarosa Manigault, in a statement released by publicist Joy Fehily.

Duncan "suffered a myocardial infarction on July 13 and never fully recovered," the statement said. "Manigault is grateful for all of your prayers and asks for privacy at this time. Celebrations of his life, both private and public, will be announced at a later date.