Pitchfork Music Festival Chicago wrapped up its 2019 iteration Sunday night. Snail Mail closed out the Blue Stage, and for her final song, she welcomed a special guest: Clairo, aka YouTube-bred pop singer Claire Cottrill, who had performed on the Green Stage earlier in the day.

The two 20-year-old artists appear to have a close bond. They sat together for an interview alongside Cuco at last month’s Primavera Sound, and Clairo recently told the Boston edition of Metro, “Lindsey is a really close friend of mine and a huge inspiration for me.” They certainly seemed to enjoy the chance to perform together Sunday night, smiling broadly all throughout their duet on “Speaking Terms” from Snail Mail’s ridiculously good 2018 debut album Lush, which finished at #2 on our list of last year’s best albums.

This was Snail Mail’s second big duet of the weekend. At an aftershow Saturday night, she welcomed Soccer Mommy’s Sophie Allison on stage to cover Goo Goo Dolls’ “Iris.” Incidentally, Jordan, Allison, and Clairo recently joked about becoming the next boygenius.

Watch Clairo join Snail Mail for “Speaking Terms” below, and check out our coverage from Pitchfork Music Festival here; more is coming today.