David Tennant was worried about reprising his role for the 50th anniversary episode of Doctor Who as he feared working with Matt Smith would be weird.
Tennant told Entertainment Weekly, "I'm coming back to a show that's effectively somebody else's show and used to be mine and that's potentially quite a weird situation to be in.
"Going back to something I knew so well and had so much fun memories of might have backfired."
"It's quite a rare set of circumstances: Pierce Brosnan and Daniel Craig don't get to play James Bond next to each other. But it actually felt familiar enough that it was like coming home and working with Matt proved to be a real joy."
Although he was concerned, Tennant found the experience very enjoyable and commented, "I suppose you'd expect me to say we're new best friends and I love him like a brother. But that is sort of how it was. I had a fantastic time and that wouldn't necessarily have been the case."