At 5:15pm on 23 November 1963, the first episode of Doctor Who was broadcast on BBC One.

Exactly 60 years on, the show is celebrating its diamond anniversary with three new hour-long specials starting this weekend.

For many fans, they're particularly special because they feature the return of David Tennant, who left in 2010. His tenth Doctor has arguably been the most popular with audiences since the show returned in 2005.

"To get to return to something that meant so much 15 years ago, and was such a huge part of my life, was something I never really imagined was likely," says Tennant.