Asked about his role in Doctor Who, he said: “That was my lockdown experience. I am the new companion to the Doctor. I’m allowed to say that, but that’s about it!”
However, he added that he had already received a telling-off from the BBC after telling a group of students that his character, Dan, is from Liverpool and speaks with a Liverpudlian accent.
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"The BBC phoned me up and said, 'You [committed] the cardinal sin. You've told them something about Doctor Who'," Bishop said. "I went, 'I haven't told them anything! Anybody who looks at me knows he's from Liverpool!'"
Bishop's character was previously unveiled in a special teaser at the end of New Year's special Revolution of the Daleks.
According to a BBC statement, his character Dan will become “embroiled in the Doctor’s adventures" and “quickly learn there’s more to the Universe(s) than he could ever believe”.
However, Bishop didn't initially jump at the chance to step inside the TARDIS, recently admitting he turned down the Doctor Who part before lockdown inspired him to reconsider.
Back in February, the comedian explained that showrunner Chris Chibnall had pitched the character to him, but that he was due to go on tour and the dates didn't work.
“I met [head writer] Chris Chibnall and he had this idea, and this character," Bishop said (via CultBox). "He’d seen me in a few things, and he wanted to know if I’d be interested in Doctor Who. I was flattered but the problem was I was on tour when they were meant to be filming. So although I fancied it, I had to say no.
“And then the whole COVID thing happened! Lockdown arrived so I made a phone call and fortunately they had moved their filming dates. It now fits in perfectly – I'm doing Doctor Who up until July and then I go on the road again in September.”
The Graham Norton Show airs on BBC One on Friday 16th April at 10.45pm. Doctor Who returns to BBC One in late 2021. Want something else to watch? Check out our full TV Guide or visit our Sci-Fi hub for all the latest news.