Byrne’s cause of death was not immediately revealed. The Guardian first reported his death.

Byrne appeared in films and TV shows since the 1960s, with his latest credit in 2023, according to his IMDb page.

He also held a role in Mel Gibson’s “Braveheart,” playing a violent soldier named Smythe.

Byrne started his career on the small screen, scoring roles in TV shows such as “No Hiding Place,” “Silent Playground” and “ITV Saturday Night Theatre.”

His film career took off in 1963 in “The Scarlet Blade.” The film was later retitled “The Crimson Blade” in the U.S.

Prior to that, as Variety reported, Byrne starred on stage with a number of roles in shows for Laurence Olivier’s National Theatre Company, including “Romeo and Juliet,” “The Cherry Orchard,” “Much Ado About Nothing,” “Death and the Maiden at the Royal Court,” “The Double Dealer” and “The Seagull.”

In the “Harry Potter” series, he played an older Gellert Grindelwald, a notorious dark wizard. Over his seven-decade career, Byrne racked up more than 170 credits, according to Variety, from TV to film to theater.