Taylor Swift reveals she wrote ‘Toy Story 5’ viral song in one ‘hectic day’

Taylor Swift penned I Knew It, I Knew You for the Toy Story 5 soundtrack in just a day after getting the "songwriter zoomies."

The music superstar wrote and produced the single for the new animated movie with her close collaborator Jack Antonoff, with the track inspired by the character of Jessie, voiced by Joan Cusack.

Taking to her social media accounts on Thursday night, Taylor shared a video showing her in the recording studio working on the track.

"Been kind of a hectic day," she stated, appearing a little jittery.

"At 11 a.m., went to go see Toy Story 5. Got so inspired, got the songwriter zoomies, went home, wrote the end-credit song for Toy Story 5. We have now produced it, and I'm doing vocals. It's 6:57 p.m., in two hours, (Disney boss) Bob Iger and Tom (Porter) from Pixar are coming to hear it."

While Taylor had not yet recorded the heartwarming song, she declared, "I think this is one of the most fun days of my life."

It's unclear when the footage was filmed.

And in a teaser for an appearance on Good Morning America on Friday, the Opalite hitmaker recounted how she called singer-songwriter Jack and insisted they work on the song together.

"I called Jack Antonoff, who is one of my best friends, and so I know that he is not only as big a Randy Newman fan as I am but also a Toy Story kid... We talk about Toy Story all the time and how it really shaped our childhood," the 36-year-old smiled in the clip.

"It was such a frenetic form of excitement that I just blathered out like, 'We have to write this song,'" she added.

At the world premiere of Toy Story 5 in Los Angeles earlier this month, Taylor Swift performed I Knew It, I Knew You on the piano. She also joined the franchise's long-running composer, Randy, for a rendition of his 1995 track, You've Got a Friend in Me.

Toy Story 5, featuring the voices of Tom Hanks and Tim Allen, opens in theatres on Friday.