David Tennant and Alex Kingston are reuniting for a new Doctor Who audio adventure.
The Tenth Doctor only met River Song once on screen - ironically, his first encounter with her was her last encounter with him - in the two-part series four story 'Silence in the Library'/'Forest of the Dead'.
Most of River's on-screen experience was with Matt Smith's Eleventh Doctor but a new series from Big Finish will explore Ten's other adventures with River in between their time in the library and his regeneration.
A synopsis released by Big Finish says: "The Doctor knows that River Song is a part of his future. A maddening, intriguing, but inevitable part.
"Their lives are becoming inextricably intertwined, but in these early days – for the Doctor at least – they must navigate their relationship without too many spoilers.
"Whatever her past, and the Doctor's future, holds, River will make sure that he has fun untangling the mystery..."
Doctor Who: The Tenth Doctor and River Song will be released in November.