Rey Misterio Sr. — legendary wrestler and uncle to WWE Superstar Rey Mysterio — has passed away at the age of 66, his family announced Friday.

The news was shared by the son of Misterio Sr. — real name Miguel Ángel López Díaz — on social media. Details surrounding his death were not immediately made available.

Misterio Sr. was one of the top stars in the Mexican wrestling scene, making his debut in January 1976. He famously came stateside for a matchup at WCW Starrcade back in 1990 — teaming up with Konnan.

Diaz eventually added the Sr. to his stage name so his nephew — WWE Hall of Famer Rey Mysterio — could carve out his own legacy. The two teamed up in one of Mexico’s biggest wrestling promotions — Lucha Libre AAA Worldwide — and won the WWA Tag Team championships together.

AAA shared a statement on the loss … sharing its most sincere condolences to Misterio’s loved ones.

He hung up his boots back in 2009 … ending his career having won multiple championships across various promotions. Misterio Sr. made one last appearance in 2023 at a Lucha Libre event.