Matt Smith is keen to expand Doctor Who's universe — by crossing over with some of America's best television programs. Talking to Den of Geek, he explains which TV shows he'd like to see Who cross over with, and how it could happen:
I want the Doctor to meet Heisenberg from Breaking Bad. It's amazing, he'd just go "You're a badass, man. I'm gonna make you good, I'm going to bring you back to my side; it's going to be alright dude, don't worry." I just think Bryan Cranston's incredible. I mean, there's loads of shows... Imagine if the Doctor turned up with all the zombies in The Walking Dead! He'd be like "Guys! Don't worry about it, we'll figure this out, okay... Also, can't show any blood, so can we just chill out on the eating?" He'd definitely strike up a conversation with one of the zombies, he wouldn't just shoot them; and that's the great thing about the Doctor - he'd get them talking.
Also worth reading in there: Smith's response to the 1996 Paul McGann TV movie. [Den of Geek]