It's a Dr Who's Who in Hamlet

Andrea Harris, who plays Cornelia in the Shakespearian tragedy, played UNIT agent Suzanne in The Stolen Earth - the big season four finale this year.

She worked for the American division of UNIT, and was shocked when the Earth was moved into The Medusa Cascade. She was the first in UNIT's Manhattan HQ to see the sky filled with planets.

When the Daleks were attacking the UNIT base she tried to escape but was the first one of the UNIT personnel to be exterminated.

Zoe Thorne, who plays The Page in Hamlet, has been better heard not seen in Dr Who.

She was the voice of the orb-like Toclafane in season three finale The Sound Of Drums and Last Of The Time Lords back in 2007.

Before that she was the voice of the misty Geith in 2005 episode The Unquiet Death, in which the Doctor and Rose went back in time to meet Charles Dickens.

Last, but not least, Roderick Smith - Volteman in the RSC production - played Cruikshank, one of the medics who examined the Doctor in 1977's The Invisible Enemy.

That was the story arc in which Tom Baker fell victim to an intelligent virus known as The Swarm and had to be cloned to survive. Oh, and yes, the episodes saw K9 make his debut, too.

Elsewhere in Hamlet, sci-fi buffs will already have spotted Patrick Stewart, Captain Jean-Luc Picard of Star Trek : Next Generation fame.

Stewart is scheming Claudius, and aptly cast in a play which gave us that "undiscovered country" line he trotted out in the sixth Star Trek movie.

And the excellent Oliver Ford Davies (who plays Polonius at Stratford) was, of course, Queen Amidala's Governor Sio Bibble in Star Wars Episodes 1 to 3.

Look even closer and you'll clock David Ajala, too. He plays Reynaldo in the Shakespeare play but was most recently seen as one of the bounty hunters in Batman movie Dark Knight.

The RSC production of Hamlet, directed by Gregory Doran, runs until November 15 at The Courtyard Theatre in Stratford-upon-Avon. It's a sell out so you'll have to queue for unlikely returns.

Tennant goes on to play Berowne in Love's Labour's Lost, which runs in repertoire from October 2 to November 15. For details see the RSC site or call 0844 800 1110.