Upon the mentioning of the "two universes" of
Doctor Who and
Sherlock (which Gatiss stars, writes and produces), Mark stated, "which are never going to meet!" Host Chris Hardwick pushed further, asking "Never? They can't?" to be told "No, correct."
Current
Who showrunner
Steven Moffat recently said that he would be in favour of a crossover, but was being held back by the "killjoys" in his
Sherlock team.