Sherlock show-runner Steven Moffat has said that they would never consider replacing stars Benedict Cumberbatch and Martin Freeman because "they are magic, they are the show."

The two actors, who play Sherlock Holmes and Dr. Watson respectively, are irreplaceable according to Moffat, who said that while you can admire the show's production value, it's the people you "fall in love with."

"You can admire great cinematography, a great score, great writing, great direction, great production," he told the audience at the BFI and Radio Times Festival in London.

Dream team: Benedict Cumberbatch and Martin Freeman

"You can admire all those things, but you only fall in love with people. And the people you fall in love with are Sherlock, Benedict Cumberbatch and Martin Freeman.

"You cannot replace them. They are the magic, they are the show."

Moffat, who co-created the show with Mark Gatiss, also spoke about the future of the series saying it "could be off the earth quite a long while now" because they will only make more episodes when they have the right idea.

"Neither Benedict, Mark or Martin are against doing more Sherlocks. We have a great time making them, it's a very, very nice bunch of people and we enjoy our reunions very much."

He said everyone involved in the show is "aware, very aware" how special it is to be a part of.

"And that means two things, we'd never want to do it if we didn't think we could do it as well as we used to," he said.

"It also means we'll come back to it when we feel we've got the right idea. It could be off the earth quite a long while now.