John Barrowman is "really upset" not to be taking part in the 'Doctor Who' 50th anniversary episode.

The 46-year-old actor insists he hasn't been approached to reprise his role as Captain Jack Harkness - who he also played in spin-off show 'Torchwood' - and if he had, bosses on his current drama 'Arrow' had already agreed to alter filming schedules to accommodate the sci-fi special.

He told TV Line: "Everyone on Twitter tries to make it like it's my decision, but the bottom line is I was not asked.

"[The producers] don't want to put Jack in it. And I know fans are really upset about it, as was I.

"People have tried to say it's my schedule - it's absolutely not. I was told by the producers of 'Arrow' that if I was asked to do the 50th anniversary of 'Doctor Who' they'd let me go and do it.

"It was nothing to do with my schedule. It's just a matter of fact that I wasn't asked."

However, John insists he understands the decision as his character may not offer appeal to the "wider audience".

He added: "I understand why they did it. They want to move forward, they want to try some different things.

"I know from how [former showrunner Russell T. Davies] approaches things, they're not doing it just for the uber fan; they're doing it for the wider audience. And if they're going to bring a character back it wouldn't be just for the uber fan, it would be for everybody. So perhaps that's the thinking they had."