Duncan, who is known for his Oscar-nominated role in The Green Mile, has died, reports the Associated Press. The wire service is attributing the news to his fiancee, Omarosa Manigault.
Duncan was hospitalized in Los Angeles after a heart attack in July.
At that time, publicist Joy Fehily said in a brief e-mail statement that the 54-year-old actor suffered a myocardial infarction.
As soon as the news broke, Hollywood stars began sharing their reactions on Twitter. Here are some:
Jordin Sparks: "RIP Michael Clarke Duncan. Thank you for being so kind to me & for sharing your talent with the world. You will be truly missed."
Dule Hill: Life is so precious. A talented brother and a kind spirit. RIP Michael Clarke DuncanNiecy Nash: Rip Michael Clarke Duncan. We shared sum great times! C u on the other side friend... @OMAROSA praying 4 u & the fam
Dule Hill: "Life is so precious. A talented brother and a kind spirit. RIP Michael Clarke Duncan"
Niecy Nash: "Rip Michael Clarke Duncan. We shared sum great times! C u on the other side friend... @OMAROSA praying 4 u & the fam"
Mario Lopez: "R.I.P Michael Clarke Duncan... One of the nicest & most professional guys I've had the pleasure of knowing. So sad..."
Michael Chiklis: "R.I.P. Michael Clarke Duncan. :.("
Lorena Blas, USA TODAY