Michael Clarke Duncan is in the intensive care unit of a Los Angeles hospital after going into cardiac arrest.
The Green Mile actor is believed to have been discovered by his girlfriend Omarosa Stallworth at around 2am this morning.
She performed CPR on location and managed to revive the 54-year-old.
The star was then transported to a nearby hospital where he was immediately admitted to the intensive care unit (ICU) for treatment.
"Sources tell us... Duncan's heart rate is now stable and Omarosa is by his side. Doctors are performing tests to figure out why the actor's heart stopped in the first place," reports TMZ.
Duncan is currently starring in US TV show The Finder.
His breakout role as prisoner John Coffey in the 1999 fantasy movie The Green Mile - also starring Tom Hanks - earned him best supporting actor nominations at both the Academy Awards and Golden Globes.
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