“What’s this?” Jack was poking around in the TARDIS’s wardrobe, looking for something to wear since Rose had insisted his World War Two garb, although cool, was too outdated for day-to-day wear.
“Hm?” The Doctor turned to see Jack holding up a white jumpsuit, covered in coloured rhinestones and with a very impressive belt buckle. “Oh, that was one of Elvis’s stage costumes. He gave it to me, well, a former version of me, as a thank you gift after I took him on a trip.”
Jack frowned. “Who’s Elvis?”
“Big rock and roll star, very famous. Before your time.”