The actor had been moved into hospice care just a few hours earlier on Friday.
Varsity Blues star Ron Lester died Friday in Dallas of organ failure. He was 45.
Dave Bradley, Lester's agent, confirmed to ET that the actor died at 8:57 p.m. local time in Dallas, his fiancée, Jennifer Worland was with him at the time of his death. Lester was not in any pain "as he was medicated enough to be able to go peacefully."
Earlier in the day, Lester was transported from an intensive care unit to hospice care after suffering liver and kidney failure. He had been in the hospital for four months, and even tweeted an update about his condition in November. "Liver and kidneys are starting to heal. Came close to dying! Without my fiancé Jennifer Worland, I wouldn't be alive!" he wrote.
Lester's friends and former co-stars have begun sharing their condolences on social media.
"Sad day... #RonLester was a sensitive soul with a huge heart," wrote James Van Der Beek, who co-starred with Lester on Varsity Blues. "Everything you loved about Billy Bob was authentically Ron. #RIP bud."
"Rest in peace, old friend. I'm glad I knew you. Heartbroken for his fiancé, family and friends," Lester's Popular co-star Christopher Gorham wrote.
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Lester's friend, Bryce Johnson, shared a similar sentiment. "To my good buddy #RonLester you always made me smile brother," he wrote alongside an image of Lester and Paul Walker, who both worked together in Varsity Blues. "I was blessed to have known ya. May you rest in peace."
"Did I throw away my career to be skinny? Yes," Lester told Grantland in 2014. "I wouldn't do [the surgery] again. I would much rather have died happy, rich and kept my status and gone out on top."
The Georgia native was best known for portraying Billy Bob in 1999’s Varsity Blues. His first role was on a commercial for Formula 409, and he moved to Los Angeles in the mid-90s, working on a stand-up comedy routine before landing a role in 1997’s Good Burger. He also appeared in Not Another Teen Movie and The Greenskeeper, had recurring roles on the small screen in the series Popular and Freaks and Geeks, and guest starred on CSI: NY and Sabrina, the Teenage Witch.
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This is the second heartbreaking loss for the Varsity Blues family in recent years. Walker, who played Lance Harbor in the football film, died at age 40 in a car collision in Santa Clarita, California, in November 2013.
Walker's Fast and Furious franchise co-star, Vin Diesel, got emotional earlier this year when he paid tribute to the late actor at the People's Choice Awards. Watch Diesel’s emotional speech in the video below.