LONDON — A Mexican wrestler and actor who appeared in the movie “Nacho Libre” died in the ring during a bout in London on Saturday, according to the venue where the event was held.

The wrestler, César González Barrón, known as Silver King, was facing off against an opponent known as Juventud Guerrera, or Youth Warrior, when he became unresponsive at the Roundhouse, a performing arts and concert venue in Camden.

In footage shared online, Mr. Guerrera appeared to kick Mr. González Barrón during the match and tried to pin him down for the victory. The footage also showed the referee and others trying in vain to revive Mr. González Barrón.

According to the Mexican news outlet Record and other reports, Mr. González Barrón appeared to have died of a heart attack, but officials have not yet released an official cause of death.