Publicist Joy Fehily says in a brief email statement that the 54-year-old actor "suffered a myocardial infarction" early Friday.
She says his heart rate has stabilized and he's expected to make a full recovery.
Fehily wouldn't confirm a TMZ.com report that Duncan's actress-girlfriend, Omarosa Manigault-Stallworth, discovered the former bodyguard in distress at about 2 a.m. Friday in his Los Angeles area home and revived him by performing CPR. Representatives for the actress didn't immediately respond to requests by The Associated Press for comment.
Besides "The Green Mile," Duncan appeared in the films "The Scorpion King," ''Armageddon," ''Breakfast of Champions," ''The Whole Nine Yards" and "Sin City."
Stallworth has appeared on TV's "The Apprentice," ''Fear Factor" and "Girls Behaving Badly."