British actor William Morgan Sheppard has died at the age of 86.

The actor's son, Supernatural star Mark Sheppard, confirmed the news of his father's passing on Instagram Sunday evening by writing, "We went to spend some time with my father today. Though he couldn't speak, we held hands, he laughed and was so happy to see us. We left and came home. A good day. He was rushed to hospital and passed at 6:30pm, my mother by his side. I am so grateful that he didn't have to suffer any longer. Thank you for all your kind thoughts, love and prayers."

Sheppard was known for his many appearances across the Star Trek franchise, including guest-starring on episodes of Star Trek: Voyager ("Bliss") and Star Trek: The Next Generation ("The Schizoid Man") and appearing in the filmsStar Trek VI: The Undiscovered Country and the 2009 reboot Star Trek. Additionally, he was well-known for his work as Blank Reg in the short-lived, cult classic ABC sci-fi Max Headroom and starred in two episodes of Babylon 5.

The actor also starred as Old Canton Delaware alongside son Mark Sheppard in a 2011 episode of Doctor Who ("The Impossible Astronaut") and enjoyed a litany of guest roles in popular shows like Charmed, Alias, Gilmore Girls, Criminal Minds, NCIS, Mad Men, Dexter, and It's Always Sunny in Philadelphia. On the film side, he was perhaps best known for his roles in The Prestige and Transformers, but his earliest films included Strongroom, Tell Me Lies and The Elephant Man. His last film was 2016's Last Man's Club.

In addition to his screen work in films and television, Sheppard was also an accomplished voice actor, lending his vocals to series like Hellsing, Legend of the Seeker, and The AOF Channel.

Sheppard first got his start in the theater, graduating from Royal Academy of Dramatic Art (RADA) and training with the Royal Shakespeare Company. Of his decision to pursue acting, Sheppard explained (via WhatCulture), "I wanted to be a stand-up comedian, I did some gigs... I had a good job selling building equipment, but was itching for something - I was not so funny, but I had good timing." He went on to make a splash on Broadway with his 1966 appearance in Marat/Sade.

Prior to studying acting, Sheppard served in the Merchant Navy and credited that experience with informing his screen and stage-work by saying, "My experience in the Merchant Navy gave me an edge at RADA and in business. I was 25 and those at RADA were younger, kids really- nice kids, but immature. I had been damaged and was always able to get up off the floor, often due to the kindness of others. I have been lucky."