Porridge actor Kevin Bishop has paid tribute to the "flawless" Peter Vaughan who starred in the sitcom's original run.
Peter died at the age of 93 on Tuesday morning, his agent said.
Kevin was part of the show's one-off revival earlier this year and will return as Nigel "Fletch" Fletcher, the grandson of Ronnie Barker's famous character, Norman Stanley Fletcher, for a full series.
Despite being in only three episodes of Porridge alongside Ronnie, as well as the 1979 film version, Peter made his mark as villain Harry "Grouty" Grout.
Kevin, who has previously called it an "honour" to star in the show's revival, said Ronnie relied on Peter's combination of comedy and deadliness to pull of the role of Fletcher.
He told the Press Association: "Peter Vaughan had an incredible career.
"One of the truly great character actors of our time.
"Without Vaughan's flawless comic performance layered with chilling coldness as Harry Grout in Porridge, there would be no fearful high stakes for Fletcher, something you need desperately in a prison comedy.
"To have such comic ability and dramatic skill is rare and he will be sadly missed."
Peter was more recently known for his role as Maester Aemon in TV hit Game Of Thrones.
The BBC said production of the new series of Porridge will begin in January 2017.
The show's original writers, Dick Clement and Ian La Frenais, will script the six episodes.