曾有两次：《神秘博士》2017圣诞特别篇

PeterCapaldi’sfinalepisodeofDoctorWhothisChristmaswillfeaturePearlMackieasBillPottsandbecalledTwiceUponaTime,itwasrevealedthisevening(23July)duringacastpanelatSanDiegoComicCon.ViewerswillhavetowaituntilChristmastodiscoverexactlyhowBill,whowillappearthroughouttheepisode,makesherreturn.