Jan. 8 (UPI) -- Former ER star Dearon "Deezer D" Thompson has died.
On Thursday, the actor and rapper was found unresponsive at his home in Los Angeles, according to TMZ. Thompson was 55.
Thompson's brother, Marshawn, said the actor died of a suspected heart attack. Officials have yet to determine an official cause of death.
Deadline said Thompson had undergone multiple heart surgeries in the past decade.
Thompson played Nurse Malik McGrath on ER throughout the show's 15-season run on NBC. His former co-stars Mekhi Phifer and Noah Wyle were among those to mourn the actor's death on social media.
"What a special spirit we have all lost! Since the first day I met him on the set of ER he absolutely made me feel at home and welcomed. My brother will forever be missed! Many condolences to his friends, fans and family. RIP Deezer D!" Phifer, who played Dr. Gregory Pratt, wrote on Instagram.
"I lost a dear friend yesterday," Wyle, who played John Carter, said. "He was one of the most creative and charismatic men I've ever known and his gospel of positivity pulled us both up from many a dark place. I will miss him terribly. Please say a prayer for him and hold a loving thought for his family today."
Thompson's other TV and film credits include Romy and Michele's High School Reunion and CB4 co-starring Chris Rock. He was also a rapper whose new song, "History Can't Be Stopped," was released posthumously today.