Cedric McMillan, a world-class bodybuilder and former U.S. Army instructor at Fort Jackson in South Carolina, died earlier this week, according to multiple reports. He was 44.

Generation Iron and RXMuscle both reported McMillan's death. According to Generation Iron, McMillan suffered a heart attack while he was working out on a treadmill.

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Cedric McMillan

Cedric McMillan performs in the Arnold Classic Men's Bodybuilding Open on March 19, 2016, in Melbourne, Australia.  (Quinn Rooney/Getty Images)

"Cedric, a truly great bodybuilder and one of the most entertaining to ever grace the stage, will be remembered for his generosity toward his fans. He gave his time and energy toward connecting and inspiring, completely aware of his stature as a bodybuilding icon," RXMuscle wrote on Facebook on Tuesday.

"Cedric was an American hero, who was proud to be an American and to serve his country in our armed forces. We will never forget his service to our country.

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Cedric McMillan

Competing in the Arnold Sports Festival on March 7, 2020, in Columbus, Ohio, are, from left, Maxx Charles, Cedric McMillan and Sergio Oliva Jr. (Frank Jansky/Icon Sportswire via Getty Images)

"A dedicated family man, Cedric was a pure inspiration for bodybuilders and people to look up to."

Fellow bodybuilder Kai Green also paid tribute to McMillan on his Instagram account.

"Feeling uneasy with the news of your sudden departure from this dimension to the next. @cedricmcmillan was a father, a friend, a competitor, a man of uniform, a man of many hats who always knew how to make other people laugh and make everyone around him feel like family," he wrote Tuesday.

McMillan won the Arnold Classic in 2017 and finished in sixth placed in the Arnold Classic Columbus in 2020.

Cedric McMillan

Arnold Schwarzenegger interviews Cedric McMillan after McMillan won the Arnold Classic on March 4, 2017, in Columbus, Ohio. (Frank Jansky/Icon Sportswire via Getty Images)

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In November, McMillan opened up about heart and breathing issues likely caused by COVID-19. He told Generation Iron he was put on life support. He had been optimistic about returning to the competitive bodybuilding scene.