Alex Kingston has hinted that time-traveller River Song could be back on Doctor Who in the future.
The actress - who can soon be seen in the new series of Upstairs Downstairs - told talk-show host Graham Norton that she may be resuming her Who role.
"You may see her again. Who knows?" she said. "Let's just say, Upstairs Downstairs and Doctor Who don't film at the same time."
In an interview set to air on Friday at 10:35pm on BBC1, Kingston also confessed that she had known "for a very long time" that her character was secretly the daughter of the Doctor's assistant, Amy Pond (Karen Gillan).
"I knew...for the whole of the last series," she admitted. "[The other actors] didn't know and were constantly trying to get it out of me. They discovered it in that episode [A Good Man Goes to War] when they read the script."
River Song was first introduced in the 2008 episode Silence in the Library, which starred David Tennant. Since then she has periodically reappeared during Matt Smith's tenure as the Time Lord, most recently in the series six finale, The Wedding of River Song - the trailer for which can be found below: