Taylor Swift mentioned Aaron Dessner of the National during the Surprise Songs segment of her current Eras event. Dessner joined Swift onstage yesterday night (June 17) in Pittsburgh to play piano for the live release of the folklore tune “Seven.”

Dessner’s unscheduled presence in Pittsburgh was his third on the tour. He previously performed with Swift in Nashville in May for the live debut of “Would’ve, Could’ve, Should’ve” and in Tampa in April for “The Great War.”

“A lot of you know who this man is right here,” Swift said Saturday night in her introduction of Dessner (of course also known for his work as a founder of The National), eliciting a roar of applause. “This is what I would categorize as a soulmate collaborator. He’s the most incredible musician, instrumentalist, songwriter, and producer, and without him, folklore wouldn’t have happened.”

Swift also took a moment to thank the “amazing fathers” in the audience for bringing their children to the event and wished them a Happy Father’s Day. She mentioned Dessner in her address, calling him a “great dad,” before moving on to her own father.

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“I was thinking about the song we were gonna play because I actually – I’m not trying to brag – I have a really, really incredible dad, like hasn’t missed a show type of dad. … The song we’re gonna play has to do with having really fond memories of childhood, and growing up in Pennsylvania.”

Dessner and Swift have a long history of collaboration. He co-wrote and co-produced Swift’s 2020 albums folklore and evermore, and he contributed to Midnights last year.Other special guests on the Eras Tour have included Jack Antonoff, Marcus Mumford, Maren Morris, and Ice Spice, in addition to Dessner.Swift has also appeared alongside Phoebe Bridgers on many instances when she opened.