Leon Vitali, the “Barry Lyndon” actor who became one of Stanley Kubrick’s closest associates, has died. He was 74.

Vitali died Friday in Los Angeles, his family told The Associated Press Sunday.

Though Vitali was often described as Kubrick’s assistant, Tony Zierra’s 2017 documentary ” Filmworker” shed light on Vitali’s enormous and largely unsung contributions to the work of one of cinema’s greatest figures from “The Shining” through “Eyes Wide Shut.” He did everything from casting and coaching actors to overseeing restorations. Vitali even once set up a video monitor so that Kubrick could keep an eye on his dying cat.

Matthew Modine, who starred in Kubrick’s “Full Metal Jacket,” tweeted his condolences Sunday.

“There are people we meet who have a profound impact upon our lives. Leon Vitali was one such person in mine,” Modine wrote. “An artist in every aspect of his life. A loving father & friend to so many. A kind, generous & forgiving nature. He exemplified & personified grace.”

Filmmaker Lee Unkrich also tweeted that he was, “Completely heartbroken to hear about the passing of Leon Vitali. He helped me (asterisk)enormously(asterisk) with my Shining book and I’m gutted that he won’t see it. He was a sweet, kind, humble, generous man and a vital part of Stanley Kubrick’s team.”

Before meeting Kubrick, Vitali was a rising actor in England, appearing in several British television shows including “Softly, Softly,” “Follyfoot,” “Z Cars” and “Notorious Woman.” Then in 1974 he got his biggest break yet, when he was cast in “Barry Lyndon” as Lord Bullingdon, the son-in-law of Ryan O’Neal’s title character.

Vitali was so fascinated by Kubrick and his processes that he made an unusual decision: He gave up on acting and devoted himself entirely to the famously demanding director for over two decades. His next Kubrick credit was as “personal assistant to the director” on “The Shining,” though that’s only part of the story — Vitali famously helped cast 4-year-old Danny Lloyd to play Danny Torrance and Louise and Lisa Burns as the creepy Grady twins (citing Diane Arbus as inspiration).

“I made one truly, truly radical change in my life and that was when I said, ‘I’m more interested in that’ than I was in the acting,” Vitali told the Associated Press in 2017. “That’s the biggest conscious decision I’ve ever made. There were some sacrifices, but there were gains too.”

After Kubrick’s death in 1999, Vitali oversaw restorations for many of Kubrick’s films. He received a Cinema Audio Society award for his work. Vitali later worked with director Todd Field on his films “Little Children” and “In the Bedroom.”

Before making the documentary, Zierra said that he and many Kubrick-obsessed fans knew Vitali for his performances in “Barry Lyndon” and “Eyes Wide Shut,” in which he played Red Cloak, and as a key member of Kubrick’s inner circle. But when they finally met Vitali to make the film, they were struck by “his kindness, humility and the fascinating scope of his story.”

Zierra is working on a director’s cut of “Filmworker” that will include new footage that he and Vitali wanted in the film, but couldn’t get done in time for its Cannes debut in 2017.