Richard Simmons, the legendary fitness instructor who reached massive celebrity status, has died at the age of 76, KTLA has confirmed.

The Los Angeles Fire Department told KTLA that it received reports of a “cardiac arrest suspected death” at 1350 Belfast Drive in the Hollywood Hills at 9:55 a.m.

Officials called the death “natural.”

He celebrated his 76th birthday on Friday. On X, formerly Twitter, he thanked fans for the well wishes.

“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 March, Simmons announced he was diagnosed with skin cancer after finding a bump under his right eye. As of Saturday, there was no word as to whether that contributed to his reported death.

Born and raised in Louisiana, Simmons moved to L.A. in the 1970s. There, he began to pursue his career as a fitness instructor. He opened a fitness studio, SLIMMONS, in Beverly Hills and later starred in the nationally syndicated “The Richard Simmons Show” where he gave fitness instructions to viewers at home.

Celebrities took to social media to react to the loss of an American icon.

TV host and actress Ricki Lake said she loved Simmons “so so much” on a post to X.

“My heart is broken with the loss of this super special human,” she said.