Sherlock executive producer Steven Moffat teased last week that the new season will be much darker than seasons past, stating that parts of Season 4 will be "bloody frightening." While fans continue the long wait for Season 4, which won't air until early 2016, Steven Moffat is also working on Season 9 of Doctor Who, slated to debut sometime this fall on both BBC and BBC America. Since Steven Moffat serves as the head writer and executive producer on both shows, many fans have wondered about the possibility of a crossover, especially since Steven Moffat teased last year that he is open to the idea. However, the writer-producer revealed in an interview with Entertainment Weekly that he wants to give the people what they want in a crossover, but executive producers Mark Gatiss, Sue Vertue and Sherlock stars Benedict Cumberbatch and Martin Freeman have persuaded him that a crossover is a bad idea.

"My instinct - and this is probably from years of doing Doctor Who - is I'm just such a tart. If people want to, we should give it to them. But I got persuaded by Mark, Benedict, [executive producer Sue Vertue] and Martin saying, 'Look, it will never be as good as they think it's going to be,' and then I say, 'Yes, but we'll just bang it out and make it as good.' 'Yeah, but you can't give everybody everything they want all the time.' I'm in the camp of giving them everything they want. But I think they're sane and right and I'm just a tart."

While the Sherlock stars and producers may not be on board with a crossover, it isn't known how Steven Moffat's Doctor Who stars Peter Capaldi and Jenna Coleman feel about the idea. Even if Sherlock stars Benedict Cumberbatch and Martin Freeman were on board, it could be difficult to bring them back for a crossover, given how their careers have skyrocketed since the show debuted in 2011. It's worth noting that in several Doctor Who tie-in novels, the Time Lord has made passing references to his friendship with Sherlock Holmes, but, on the other hand, the characters have never been seen on screen together, or mentioned each other in their respective shows.

Would you like to see the stars align for a Sherlock and Doctor Who crossover? Or do you agree with Benedict Cumberbatch and Martin Freeman, who don't think a crossover will be as good as some fans may think? We'll keep you posted if this crossover ever comes to fruition, and stay tuned for more updates on both Sherlock and Doctor Who.