Joe Alwyn was later recognized as a co-producer of Taylor Swift's “august” after Folklore's Grammy win.
The song's liner-note production credits list Swift and Jack Antonoff, while the Recording Academy recognized Alwyn as a co-producer after Folklore won Album of the Year at the 63rd Annual Grammy Awards. Alwyn used the pseudonym William Bowery for some songwriting and production work on Swift's albums.
Alwyn's credit is connected to the finished production rather than the song's main public songwriting identity. Swift and Antonoff wrote the song, and Antonoff helped construct its instrumental foundation.
This detail is often confused with the credits for other Folklore songs. Aaron Dessner was a major collaborator on the album, and Laura Sisk was an engineer, but neither is the answer to this specific co-producer question. The Grammy-related recognition is what makes Alwyn's role distinctive.