[Interview : Matt Smith and Collider.com]
Question: It’s really growing. I want to know if there’s any chance of an Easter-egg in Sherlock or vice-versa where Sherlock’s going on, because they’re filming in January, February…
SMITH: They are, yeah. ..
and you’re like standing in the background of the scene or reverse you’re filming and they’re standing in the background of a scene.
SMITH: I think Mark and Steven kind of hate the idea of Doctor Who and Sherlock ever meeting.
It’s be a nice Easter-egg for the fans.
SMITH: No, I know, I know, and listen I’m not averse to it. I’m kind of open. I’m like yeah, because I just think they would find each other so remarkable.
I don’t even mean like they’re having a conversation, I mean you’re just walking by in a scene.
SMITH: But how can Doctor Who walk by in Sherlock Holmes?
I don’t know.
SMITH: Because he’s fictional. Doctor Who could, but it’s just nah, it’s you know—and The Doctor with Watson, he’d be like, “Cheer up mate. It’s not that bad, I know you’re really clever, but there’s an alien over there, let’s go and talk. He’s got wiggly bits on.”