The Friends alum and Swift each strummed acoustic guitars as they sang the signature song from Kudrow's character Phoebe Buffay during Swift's fifth and final concert at the Staples Center.
Check out video of Kudrow and four more head-scratching cameos:
1. Swift and Lisa Kudrow perform "Smelly Cat" - Los Angeles, Aug. 26
2. Ellen DeGeneres sparkles to "Style" - Los Angeles, Aug. 24
3. The U.S. women's soccer team joins Swift onstage - New Jersey, July 10
4. Uzo Aduba performs "White Horse" - Los Angeles, Aug. 22
5. Mariska Hargitay struts down the catwalk - Philadelphia, June 13