Alex Kingston reprises her role as River Song in Saturday’s Doctor Who and travels back in time for the new season of Upstairs Downstairs . I talk to the former ER star about River, Downton Abbey , historical lesbians, and more. Over at The Daily Beast, you can read my latest feature, "Alex Kingston's Journey Through Time," in which I talk to Kingston about Doctor Who and "The Angels Take Manhattan," Upstairs Downstairs (which returns to PBS' Masterpiece on Oct. 7), Downton Abbey , River Song, historical lesbians, and more. Upstairs Downstairs isn’t typically known for its salaciousness. The costume drama’s legendary original run—between 1971 and 1975 on ITV—kept the characters’ sexuality more or less off-screen, but the recent BBC revival series, which returns to PBS’ Masterpiece on Oct. 7, has taken a more overt approach to human sexuality than its predecessor, with one character—Claire Foy’s Lady Persephone—painted as a notorious Nazi sympa