"Nelsan has passed away after complications with heart failure," his manager, Emily Gerson Saines, told the Hollywood Reporter. "He was a great talent, and his words and presence will be forever missed."
In addition to portraying Lafayette Reynolds on "True Blood," Ellis also appeared in "Veronica Mars," "The Soloist," "The Help" and "Lee Daniels' The Butler."
News of the actor's death was met with an outpouring of condolences by colleagues and fans on social media.
"Crushed today by the loss of my friend and castmate Nelsan Ellis," Joe Manganiello wrote on Twitter. "He was a wonderful person, a pioneer, and a one of a kind artist. RIP"
Crushed today by the loss of my friend and castmate Nelsan Ellis. He was a wonderful person, a pioneer, and a one of a kind artist. RIP pic.twitter.com/fvtquhIac7— Joe Manganiello (@JoeManganiello) July 8, 2017
"My God, such a beautiful soul and talented artist," Gabrielle Union tweeted. "Blown. Away. #RIP"
Ellis was born Nov. 30, 1977, in Harvey, Illinois. After a short stint in the U.S. Marines, which he quit at age 17, Ellis enrolled at the Juilliard School in New York. He graduated in 2004.
DEVELOPING: More details will be added to this article as they become available. ABC News contributed reporting.