Running a concert like iHeartRadio’s Jingle Ball is a difficult task. There are a lot of moving parts. Sometimes the backstage décor isn’t up to par. Not all the channels on all the TVs in the artists’ dressing rooms are working. Ed “Gingerbread Man” Sheeran’s security detail is in shambles. Now there’s a dancer down! Luckily, James Corden was on hand to save the day. Filling in as the Forum’s temporary GM, Corden managed not to derail the show, putting his own body on the line as Taylor Swift’s replacement backup dancer, fishnet-adorned midriff and all. He’s not her favorite James (that would be Franco), but he’s the only James with enough patience to teach her to match pitch.