Current “Doctor Who” show runner Steven Moffat has revealed that he is open to having two key characters he introduced to the world of ‘Who’ back on the show – Captain Jack Harkness (John Barrowman) and Professor River Song (Alex Kingston). He tells Zap2It:
“It’s never, ever closed off. It’s all about ‘Do you have a story that’s worth it? Unless you’ve got a story that is absolutely informed and invigorated by their presence, just bringing a character back in an ordinary story won’t do…
Both River Song and Jack Harkness are massive characters in ‘Doctor Who’ mythology. Their returns would have to be seismic, not routine. Sometimes you have to know when a story’s over, you do. One of the things you always want to say is ‘leave them wanting more.'”
These days Barrowman and Kingston are recurring guest stars on The CW’s “Arrow,” playing parental figures to two of the key female cast members.