This Doctor Who short first appeared as part of the Children in Need charity presentation in 2007. Designed to fit seamlessly between the season three finale, and the already seen teaser for that year's Christmas special, the short is a funny crossover, that is as much a meta ode from its writer, as anything else.
Having said goodbye to Martha Jones (Freema Agyeman), The Doctor (David Tennant) has a paradoxical meeting with The Doctor (Peter Davison) when their Tardises (Tardi?) merge. The tenth Doctor tells the Fifth about how much he loved being him, and what traits he continues with - before solving an issue on board with a textbook causal loop paradox.
As I say, the episode is mostly a way for Stephen Moffat to get out his feelings for "his" Doctor, in this case Peter Davison. This is back before David Tennant would meet and marry Davison's daughter, so he gets to poke some gentle fun at his future Father-in-law's missing hair and middle-aged spread. The love from both the star and writer is palpable though.
Some funny gags and some poignant moments, all in 8 minutes of TV. The only shame is that there isn't more of it.
