The news was confirmed to BBC by his agent, who said the star "passed away peacefully yesterday after a long illness surrounded by his wife and family. He will be deeply missed."
In the first season of "The Crown," Pickup played the Archbishop of Canterbury in four episodes, while in "Darkest Hour" he portrayed Neville Chamberlain, a former prime minister of the United Kingdom.
Pickup first appeared in a 1964 episode of "Doctor Who" before jumping into more film and television roles, according to his IMDb profile.
Notably, he also appeared in the James Bond flick "Never Say Never Again" in 1983, voiced the talking lion Aslan in a 1988 miniseries titled "The Lion, the Witch & the Wardrobe," appeared in a 1990 made-for-TV adaptation of "Jekyll and Hyde" and portrayed King Sharaman in "Prince of Persia: The Sands of Time" in 2010.
In "The Best Exotic Marigold Hotel" and its sequel he played a character named Norman Cousins before appearing in an episode of "Downton Abbey."
He was nominated for a BAFTA TV Award for his role in the 1983 TV movie "Waters of the Moon."
His final film, "Schadenfreude," starring Sir Ian McKellen, is currently in post-production.
According to BBC, in 2012, Pickup told the PA news agency that the role he was most fond of was when he played George Orwell as he wrote the acclaimed novel "1984."
The role was for a made-for-TV movie called "Crystal Spirit: Orwell On Jura."
He also worked on stage, having appeared in the play "Amy's View," in 1999, per IBDB.
London's National Theatre released a statement Thursday, in which it remembered him for participating in 36 productions, starting with 1964's "The Royal Hunt of the Sun."