Cumberbatch to play the Master for Doctor Who's 50th?

Rumours of Benedict to face Matt for the 50th Anniversary of Doctor Who as the Master

With Moffat at the helm of both Sherlock and Doctor Who, it's no surprise that this is a possibility.
While Benedict was a possible 11th Doctor, a source has told the Express that he is to play the Master in Doctor Who's 50th Anniversary;

“It’s fitting that the Doctor comes face to face with his ultimate enemy, The Master, for the 50th anniversary and it’s felt Benedict is the perfect choice if schedules can work. Fans will love the idea of the man who plays Sherlock Holmes taking on the Doctor.”