Simmons has been out of the public spotlight since 2014 and was found dead one day after his birthday.
WASHINGTON — Fitness guru Richard Simmons died Saturday at the age of 76, his representative and law enforcement sources confirmed to multiple media outlets.
Simmons, a best-selling author and star of millions of exercise videos - including the Sweatin' to the Oldies” line - had just celebrated his birthday on Friday. He had posted a thank you on social media for all of the messages he'd received, less than 24 hours before his death.
"Thank you…I never got so many messages about my birthday in my life! I am sitting here writing emails. Have a most beautiful rest of your Friday," Simmons wrote in a social media post Friday afternoon.
TMZ, which was first to report his death, said emergency crews responded to a call from a housekeeper Saturday morning and pronounced Simmons dead at the scene. According to the outlet, no foul play is suspected.
Law enforcement sources confirmed to NBC News that Simmons was found unresponsive Saturday at his Hollywood Hills home. A representative for Simmons confirmed the fitness icon's death to ABC News.
Simmons has been out of the public spotlight since 2014, an absence which inspired the hit 2017 podcast “Missing Richard Simmons.” Earlier this year, Simmons spoke out against a planned biopic about him starring Pauly Shore.
Simmons was a former 268-pound teen who shared his hard-won weight-loss tips as host of the Emmy-winning daytime "Richard Simmons Show," author of best-selling books and the diet plan Deal-A-Meal, as well as opening exercise studios and starring in millions of exercise videos, including the successful “Sweatin' to the Oldies” line.
Simmons was a native of New Orleans, a chubby boy named Milton by his parents. He renamed himself “Richard” around the age of 10 to improve his self-image. He would tell people he ate to excess because he believed his parents liked his older brother more. He was teased by schoolmates and ballooned to almost 200 pounds.
Back in March, Simmons apologized after a cryptic post on social media made some of his fans think he was dying at the time. It began when Simmons shared a series of posts on Facebook and X, formerly known as Twitter, that discussed how he, along with everyone else in the world, was "dying." He went on to encourage people to live life to the fullest every single day.
"I have some news to tell you. Please don’t be sad. I am ….dying. Oh I can see your faces now. The truth is we all are dying. Every day we live we are getting closer to our death," Simmons wrote initially.
As concerns grew, Simmons clarified hours later that he was, in fact, not dying and apologized for any "confusion" he may have caused earlier in the day.
The Associated Press contributed to this report.