Taylor Swift Gets a New Backup Dancer in James Corden

James Corden came to the rescue when one of Taylor Swift's backup dancers was down.

Filling in for the general manager of The Forum last week at the iHeart Jingle Ball concert, the host of The Late Late Show made the rounds backstage, making sure that everything was running smoothly and all of the stars were ready to perform. But then tragedy struck.

"Hello. This is the general manager. What? Taylor Swift? One of the dancers is down? I can fix this," Corden said after receiving an urgent call. "I will fix this right now. I'll be right there!"

Running to the rescue, Corden crashed the singer's backstage choreography rehearsal dressed in a fishnet shirt with a crop top sweatshirt over it. He nailed every move and even added in his own vocals to "Look What You Made Me Do."

Unfortunately, Swift and her crew ditched Corden at the last minute, meaning he likely won't be showing up with her on tour.

Corden also acted as Ed Sheeran's security guard, gave Niall Horan a massage, and created a special handshake with Demi Lovato.