曾有兩次:《神秘博士》2017聖誕特別篇

地區：英國

年份：2017

演員：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 / 傑瑞德·加菲爾德

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.