Tony Burton arrives at the 'Rocky Balboa' world premiere at Grauman's Chinese Theatre in Hollywood. Credit: Albert L. Ortega/WireImage

Rocky actor Tony Burton has died at the age of 78, MLive.com reports.

Burton's costar Carl Weathers tweeted about the news on Thursday, February 25. "@E_Woodyard @TheSlyStallone Sad news. RIP Tony Burton," Weathers, 68, wrote. "His intensity and talent helped make the Rocky movies successful. #BePeace."

Burton's younger sister Loretta "Peaches" Kelley also confirmed the news. The star passed away in California.

Burton is best known for playing Duke, Apollo Creed's trainer, in the first six installments of the Rocky franchise. In real-life, the Flint, Michigan, native fought professionally and won Flint Golden Gloves light heavyweight titles in 1955 and 1957.

According to MLive.com, Burton was in the hospital for the past year, but never received an official diagnosis. Due to health concerns, he reportedly never saw Sylvester Stallone's latest Oscar-nominated Rocky movie, Creed.

Burton also appeared in The ShiningArmed and Dangerous, House Party 2 and Hook. His last role was as Sheriff Stoker in 2007's Hack!.

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