LONDON (AP) — A well-known Mexican wrestler who co-starred in the comedy "Nacho Libre" has died of a suspected heart attack after collapsing on stage in London.

Cesar Cuauhtemoc Gonzalez Barron, the lucha libre star known as Silver King, performed Saturday night at The Roundhouse. The venue said Sunday on Twitter that he died during the event and more information about the circumstances are being pursued.

The 51-year-old Gonzalez appeared as a champion wrestler and comic villain in the 2006 movie "Nacho Libre" starring Jack Black.

Lucha Libre World, which promoted the Roundhouse event, said in a statement the star "suffered what we believe was a cardiac arrest while performing in the show and sadly passed away."

Attendee Roberto Carrera Maldonado told the BBC the wrestler's condition initially appeared "staged" as part of the fight.