'Doctor Who' &' 'Sherlock' Crossover Showrunner Steven Moffat's Last Suprise Before Retirement?

Steven Moffat, showrunner for both BBC's "Doctor Who" and "Sherlock," has announced that he will be stepping down from his position in 2017, but fans are speculating that he may have one last trick up his sleeve before his exit.

Both shows have long been rumored to cross paths at some point, even though Moffat himself had already refuted the possibility.

"That's a question that I get asked so often, and I can't keep answering it," he admitted in an interview with Collider. "It's all right for 'Doctor Who.' That's fine. But it would change Sherlock's life if he met the Doctor and knew that time travel was possible."

Moffat, who joined the sci-fi series in season 5, further elaborated why it's not possible for the two characters to meet.

"He'd have to factor that into every crime he solved," he explained. "And do we really think that Sherlock Holmes lived through a Dalek invasion? I don't think he did. I think he'd have mentioned it by now. It's not going to happen. That's just the truth of it."

He also teased fans on how he thinks the two characters will react to each other if they meet.

"I suspect it's a bit like when the Doctors meet," he said. "It's fantastic, at the beginning, and then you think, 'What the hell am I going to do with three of the bastards?'"

"It's just weird. You don't really need more than one person like that in a show."

While the showrunner himself has already squashed the rumors of a "Doctor Who" & "Sherlock" crossover, many are still speculating that he's just secretly setting up something big for his final run on both shows.

Steven Moffat will remain with "Doctor Who" until the end of season 10 in 2017. Some of his most memorable episodes include "Forest of the Dead," "Library" and the show's 50th Anniversary which introduced David Tenant as the 10th Doctor. 

"Broadchurch" showrunner Chris Chibnall will take over the show in 2018.