Carl Weathers passed away following a long battle with heart disease.

On Feb. 9, a week after the Rocky star died at age 76, the official cause of his death was revealed. According to The Blast, which cited the actor's death certificate, Weathers died naturally of atherosclerotic cardiovascular disease and had suffered from heart disease for years. He passed away at his home in Venice, Calif.

E! News has reached out to the actor's rep for comment and has not heard back.

The star, who rose to fame playing Apollo Creed in the Rocky movies and later starred on The Mandalorian, had died in his sleep early Feb. 2, his family previously confirmed in a statement to NBC News.

"Carl was an exceptional human being who lived an extraordinary life," they said. "Through his contributions to film, television, the arts and sports, he has left an indelible mark and is recognized worldwide and across generations. He was a beloved brother, father, grandfather, partner, and friend."

The actor is survived by his sons Matthew, 47, and Jason, 44, who he shared with first wife Mary Ann.

Weathers was a pro football player with the Oakland Raiders for two seasons before pursuing acting full time in the mid-'70s. He landed his breakthrough role of the boxing adversary-turned-friend of Sylvester Stallone's character Rocky Balboa in the 1976 movie Rocky and reprised the role in the first three sequels.

Stallone paid tribute to Weathers following his death, saying in an Instagram video, "I'm so torn up, I can't even tell you. I'm just trying to hold it in because Carl Weathers was such an intricate part of my life, my success, everything about it. I give him incredible credit and kudos because when we walked into that room, and I saw him for the first time, I saw greatness. But I didn't realize how great."

Weathers later appeared in 1987 film Predator with Arnold Schwarzenegger, who, after his passing, called him "an extraordinary athlete, a fantastic actor, and a great person."

Weathers later teamed up with Adam Sandler for the 1996 comedy film Happy Gilmore, playing Chubbs, the title character's mentor.

"A true great man," the actor wrote about his late costar on Instagram. "Great dad. Great actor. Great athlete. So much fun to be around always. Smart as hell. Loyal as hell. Funny as hell. Loved his sons more than anything. What a guy!! Everyone loved him. My wife and I had the best times with him every time we saw him. Love to his entire family and Carl will always be known as a true legend."

In recent years, Weathers played bounty hunter Greef Karga on Star Wars TV spinoff The Mandalorian, which earned him a 2021 Emmy nomination. Main star Pedro Pascal also paid tribute to him after his death on Instagram, posting a broken heart emoji, and writing, "Words fail.

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