Who on Who?

 was a programme on BBC Radio 2 broadcast between the first and second episodes of The End of Time. It centred on David Tennant asking questions of Russell T Davies. Though most of the questions had to do with RTD's career on Doctor Who, some concerned the show runner's broader career.

It was, in a sense, a kind of "exit interview" and one of the final appearances of either man in the British press as the "current" holders of their respective jobs.

Music
The music played during the hour had some kind of connection to the RTD era of Doctor Who, including:
 * "Mr. Blue Sky" by ELO, from Love & Monsters
 * "Voodoo Child" by Rogue Traders, from The Sound of Drums
 * "I Can't Decide" by Scissor Sisters, from Last of the Time Lords
 * "Love Don't Roam" by Murray Gold, from The Runaway Bride
 * "My Angel Put the Devil in Me" by Murray Gold, from Daleks in Manhattan/The End of Time
 * other instrumental tracks from Doctor Who episodes

Title
Despite the fact that the show was on audio, where punctuation can sometimes be ambiguous, the question mark at the end of the title was definitely a part of the title. Tennant specifically jokes about the presence of the punctuation, wondering whether he is giving the title its correct inflection.