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Taylor Swift And Jack Antonoff Are Musical Soulmates: These Pictures Prove It

Lena Dunham reveals a snap of history in the making. #whereismyCHILL

Taylor Swift's "Out Of The Woods" details a pretty shaky relationship (I'm looking at you, Harry). But one thing about the new song is still going strong: her relationship with co-writer/producer Jack Antonoff.

Tay dropped her second 1989 single at midnight (October 14), and shortly after it went #1 on iTunes, Jack and Taylor couldn't be more excited.

Antonoff's girlfriend Lena Dunham posted this throwback picture, writing, "Took this the first time @taylorswift & @jackantonoff made music together in our living room. Now they are #1 on iTunes with #OutOfTheWoods. Kvelling." I'm kvelling, too, Lena.

That's the first time they collaborated? We're looking at history, people! They're really into it -- see how music-nerdy Jack seems at his computer? And Taylor's all like, "No, we need more EMOTION."

Swift also needed her pal's tech skillz this morning when it came to managing iTunes. Turns out, buying your own song is harder than it seems.

Jack already walked into wall while walking his dog. TSwift posted this text convo, while telling fans, "Clearly, we are very nonchalant about the whole thing. #whereismyCHILL."

Taylor posted lyrics on her Tumblr, and Jack professed his love for working with her. Musical soulmates? Yes, indeed.