Deezer D, a rapper, motivational speaker and actor best known for his role on the NBC television series “ER” has died. He was 55. According to TMZ, his brother Marshawn believes the star, born Dearon Thompson, died of a heart attack, although no official cause of death has been revealed. Thompson underwent major heart surgery in 2009. Deezer D appeared in almost 200 episodes of “ER” from 1994 to 2009 as nurse Malik McGrath. In 2008, he tapped into his rap talent and released the album “Delayed But No Denied.” He was preparing to get back into the hip hop industry on Instagram, teasing a snippet of a song on Monday. His single “History Can’t Be Stopped” was released posthumously on Friday.