Smith said: “I think The Silence is going to be the scariest Who monster in a long time, definitely since the [Weeping] Angels. Steven’s [Moffat] written a killer monster there.”

On working with co-stars Karen Gillan (Amy) and Arthur Darvill (Rory), he revealed: “It’s interesting, now that we all know each other a little better, hopefully the chemistry’s flying around in a good way.”

Asked about Series 6’s guest stars, he commented: “We’ve had Lily Cole’s been in, she was great. Hugh Bonneville was wonderful, he plays a pirate in a great episode actually – that’s one of my favourites so far.”

Earlier this month, Lily Cole was revealed to be playing a “mysterious sea creature”, while Hugh Bonneville discussed filming on Twitter. Comedian David Walliams has also been confirmed to appear as an alien.

Smith described the upcoming pirate episode, written by Steve Thompson (Sherlock), as “a cracker”. He added: “Getting really wet was pretty horrendous, they had this huge rain machine, although it was pretty fun”.

Series 6 will begin on BBC One in the Spring.