The celebrity guest cameos on Taylor Swift's 1989 World Tour went to new heights on Wednesday, with Lisa Kudrow joining the pop sensation on stage to perform a duet of "Smelly Cat."

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.

Swift was also joined on Wednesday by Justin Timberlake (who performed "Mirrors" with her) and her BFF Selena Gomez (who sang "Good For You"), but it was Kudrow who undoubtedly stole the show.

Other celebs who have joined Swift onstage for stops on her 1989 tour include Beck, St. Vincent, Kobe Bryant and Alanis Morissette - and that's in Los Angeles alone.

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