Graham Norton is to star in a new episode of Doctor Who, taking his Eurovision commentary duties to an Interstellar Song Contest.

Norton, the BBC's voice of Eurovision, will meet Ncuti Gatwa's Time Lord at the 803rd annual Interstellar Song Contest, where different planets compete to be crowned winner.

"And it's not just a cameo," showrunner Russell T Davies said. "He has a whole plot twist all to himself!"

The episode will also feature fellow Eurovision fanatic and broadcaster Rylan Clark as the event's co-host, and will be broadcast on BBC One just before this year's real-life grand final on 17 May.

Norton has been the BBC's commentator for the Eurovision final since 2009.

"There's no song contest without the great man himself, and it was an honour to welcome Graham Norton to our studios in Cardiff," Davies said in a statement.

"This is the wildest episode of all, and we're lucky to have Graham adding to the mayhem."

Rylan had already been revealed as taking part in the episode, and was seen in a trailer for the new Doctor Who season welcoming fans to the out-of-this-world contest alongside a co-host called Sabine, played by French actress Julie Dray.

The new season of Doctor Who – the second with Gatwa in the lead role – will start on Saturday, 12 April.

Meanwhile, Gatwa has also been cast to play Elizabethan playwright Christopher Marlowe on stage for the Royal Shakespeare Company.