The Comeback star shocked fans when she appeared onstage at the Staples Center with a guitar and performed Phoebe's most famous song Smelly Cat in the character's strained singing voice alongside Swift.

She remained in character during the performance, with Swift saying, "What song are you going to sing, Phoebe?" and in the middle of their rendition, Kudrow cut in, as Phoebe, and told the singer, "That's good, but you have to really feel the lyrics... You'll get there."

After the show, Kudrow wrote on, "So @taylorswift13 is THE best person I've ever met. That was fun. Thanks Taylor."

Swift ended her final night in a five-date residency at the venue with more celebrity guests including Justin Timberlake, who performed his track Mirrors with Swift, and her friend Selena Gomez, who sang her new single Good For You.