Time Crash ( TV story ) Time Crash was a special " Doctor Who " " mini - episode " produced for the 2007 Children in Need appeal . It featured a brief encounter between the Fifth and Tenth Doctor s and was written by Steven Moffat . It also served as the explanation of how the Doctor ' s TARDIS was breached by the " Titanic " at the end of " Last of the Time Lords " and thus leads directly into " Voyage of the Damned " . Although some might consider it a linking scene , it was very much a part of the overall continuity of the BBC Wales series of " Doctor Who " . Former " Doctor Who " actor Peter Davison returned to reprise the role of the Fifth Doctor for the first time on television since the 1993 Children in Need special " Dimensions in Time " , with his original costume faithfully replicated . This special marked the first instance in which an incarnation of the Doctor from the classic series met an incarnation from the revived series . Synopsis . After saying his goodbyes to Martha Jones at the end of " Last of the Time Lords " , the Tenth Doctor accidentally pilots his TARDIS into the path of . . . the Fifth Doctor ' s TARDIS ! As the current Doctor muses over aspects of the Fifth , the Fifth Doctor becomes increasingly worried as their combined TARDISes threaten to rip a hole in space and time the size of Belgium ! Plot . The Tenth Doctor has just said goodbye to Martha , and is attempting to take off when the TARDIS goes haywire . Suddenly , someone else is in the TARDIS : the Fifth Doctor . The Tenth Doctor realises straight away this is his past incarnation and excitedly begins reminiscing about his adventures in his fifth incarnation , much to the latter ' s confusion . The Fifth Doctor , irritated , decides that the strange , skinny bloke in his TARDIS is an obsessive fan of his — possibly affiliated with LINDA . The Tenth Doctor , to his own bewilderment , can ' t convince his past self otherwise , butting back about the Fifth ' s need for brainy specs and a celery stick as a clothing decoration . Meanwhile , the collision of the TARDIS with its past ( or future ) self threatens to tear a hole in the universe the exact size of Belgium ( which , as the Fifth Doctor remarks , is a rather undramatic description ) . The Fifth Doctor despairs of finding a solution in time , but the Tenth purposefully , if maniacally , manipulates the TARDIS controls , and averts the disaster . The Fifth Doctor is stunned - firstly at the unexpected solution , as the Tenth has managed to create a supernova at the exact same time and place as the impending black hole to cancel it out , and then at the realisation that the other man is in fact his future self . His later self knew the solution only because he would remember witnessing it now The Tenth Doctor starts reminiscing once again , telling the Fifth Doctor that he loved being him and having his youth and optimistic worldview . He reveals that he took quite a few of his current traits from him , such as wearing trainers with his outfit and having a voice that becomes squeaky when he shouts . Plus , he demonstrates that he too has his own " brainy specs " . The two Doctors then bid each other a warm goodbye : " To days to come , " says the Fifth , raising his hat . " All my love to long ago , " replies the Tenth with a bow . The time streams then start separating . As the Fifth Doctor rejoins his , he calls out one last time , warning his future incarnation to put up his TARDIS shields . But , suddenly , it ' s too late to put up the shields , and the " Titanic " has plowed through the wall of the TARDIS . . . Crew . On initial broadcast , the only member of crew credited was writer Steven Moffat . Story notes . Production errors . " to be added "