Comedians David Mitchell and Robert Webb are to guest in Doctor Who Series 7.

The duo, best known for that That Mitchell and Webb Look and Peep Show, are voicing the robots in the second episode, Dinosaurs on a Spaceship.

The robots do the bidding for the main villain Solomon, played by David Bradley.

Dinosaurs on a Spaceship airs Saturday 8 September at 7.35pm on BBC1.