Doctor Who Series 9: Who Are The Hybrids And What Does It All Mean?
6. River Song, The Human - Time Lord Hybrid?
Alex Kingston will be back onboard the TARDIS this Christmas to encounter this new version of the Doctor and there is sure to be a lot of sharp banter between the two - and laughs for the audience. But perhaps her return is more significant than just getting the chance to see her interact with another incarnation of her 'husband'.
Conceived on the TARDIS to human parents, River Song also has Time Lord DNA; it allowed her to regenerate from the frightened little girl in Day Of The Moon into Amy and Rory's friend Mel and then into the Doctor's personal psychopathic assassin and wife.
River is a hybrid of two races that has been travelling around space and time for seven years, so her return so close after the end of series nine can't be a coincidence.