Taylor Swift knows a little something about breakup songs.For quite some time, prior to her uplifting girl power breakthrough 1989, it was the newly minted New York ambassador’s stock-in-trade, with her previous LP Red presumably inspired by her messy split from the wide-eyed actor Jake Gyllenhaal.

And, during her 1989 World Tour, Swift has been bringing out a series of singers and celebrities during her stadium shows, from the inspired (Mary J. Blige, Uzo Aduba) to the head-scratchingly random (Matt LeBlanc, Chris Rock).Well, last night at the Staples Center in Los Angeles—a venue where Swift, at 25, holds the record for most sold-out performances—she decided to bring out a kindred spirit.

“She defined the music of her decade,” announced Swift. “She inspired a generation of confessional female singer-songwriters who all of a sudden felt like you could actually say these raw feelings that you had; you could actually sing about your real life, you could put detail to it, you could get really, really mad if you wanted to. And I think it’s fair to say that so many of the female singer-songwriters of my generation, including myself, would not write the way that we do without her and her music. And she has written some of the most brilliant music—in particular probably inarguably the greatest breakup song of all time.”

Then, the one and only Alanis Morissette—a one-time Daily Beast columnist, natch—emerged for a duet of her ’90s breakup anthem “You Oughta Know” (inspired by Full House star Dave Coulier, believe it or not).Watch it here: