Taylor Swift's Toy Story 5 Song Debuts at No. 1 on the Hot 100

Taylor Swift's "I Knew It, I Knew You" has debuted at No. 1 on the Billboard Hot 100, the weekly singles chart that ranks songs by sales, radio airplay and streaming. Billboard reported the result. The song was written for the end credits of Toy Story 5, Pixar's sequel to its animated franchise.

Swift wrote the track with Jack Antonoff. According to Billboard, she wrote it in a matter of hours after an early screening of the film, finishing before the day was over.

The song's route onto the soundtrack was unusual. Randy Newman has written the original music for the Toy Story films since the first one arrived in 1995. Director Andrew Stanton said Swift was the only person he had in mind to follow Newman. While she was unavailable because of her Eras Tour, the concert tour that kept her on the road, he did not approach other artists about the song.

Swift was candid about the position it put her in. "I don't want to kick somebody off of this project that you reached out to after [me]," she said. The quote is the kind of line that shows how seriously she took the invitation, and how carefully she thought about the people already involved.

Earlier this year, Swift surprised audiences at the film's Hollywood premiere. She performed the song on stage at the Dolby Theatre, playing the piano in a full-length gown and singing alongside Newman. Billboard also reports that she later joined Stanton for a question-and-answer session after a special screening.

When the song was announced, Disney described it as "a return to country," a phrase Variety reported at the time. The description places the track in a genre Swift has returned to before, though the song's chart debut is what the numbers now show.

For anyone who has ever bought a single or streamed a soundtrack on repeat, the No. 1 debut is a clear milestone for a song that began as a late addition to a family film.