Coleman's family has asked fans to pray for him after he was admitted to hospital with a brain haemorrhage.
The 42-year-old actor, who is best known for his stint on TV series Diff'rent Strokes in the 1980s, was admitted to Utah's Provo hospital on Wednesday.
He is on life support and unconscious.
His family said that Coleman's condition worsened yesterday and that he slipped into unconsciousness.
Coleman has lived in Utah since 2005, when he came to star in the movie Church Ball, a comedy based on basketball leagues formed by members of The Church of Jesus Christ of Latter-day Saints.
Been confirmed on Sky News that he has passed away
