Total fan service, but it's short and Tennant and Davison are great together.

Brilliantly written, and David Tennant is, as usual, awesome. The paradox is playfully, if not that innovatively, handled. Unfortunately, the unsubtle meta-references go a little too far at the end.

It would take Steven Moffat to bring us a doctor-crossover in the revived series. And while the episode itself was gimmicky and a bit too in love with its own mythology - it was nice to see it being ackknowledged. Rich history should not be ignored, and if the price for that is a heavyhanded reference once in a while, then so be it.

This is a fan boys dream, when more than one Doctor comes together. The return of the 5th is an inspired choice marked by the similarities between him and 10. Also Peter Davison looks quite at home in his costume, he's still got it. 7 minutes of all and out enjoyment with a kick of drama. Love this scene in every way. Part of me wishes it had been a full episode.

A must-see for fans either by David Tennant, Peter Davison or the Doctor Who series!

It's complete and utter fan-service, but Tennant really was magnificent as the Tenth Doctor and his enthusiasm upon meeting his past self really helps to bring that home. Sure, there are a couple too many typically Comic Relief cheesy jokes that spoil the moment, but for a seven minute short the plot and script are generally pretty good. Well worth a watch for any Doctor Who fan.

Cute