主演：彼得·卡帕爾迪 大衛·布拉德利 馬克·加蒂斯 珀爾·麥基 莉莉·崔佛斯 杰瑞德·加菲爾德 朱迪·惠特克 托比·懷特豪斯
導演：瑞秋·塔拉蕾
簡介：Peter Capaldi’s final episode of Doctor Who this Christmas will feature Pearl Mackie as Bill Potts and be called Twice Upon a Time, it was revealed this evening (23 July) during a cast panel at San Diego Comic Con. Viewers will have to wait until Christmas to discover exactly how Bill, who will appear throughout the episode, makes her return.