Disney created a “decoy version” of Toy Story 5 to keep Taylor Swift’s involvement a secret, even from the cast and crew.

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Yesterday (June 5), Swift shared ‘I Knew It, I Knew You’, a song she wrote and produced alongside Jack Antonoff specifically for the film. The track is written from the perspective of cowgirl Jessie, and it sees Swift going back to her country roots.

The film is released on June 19, but Swift’s involvement was only officially confirmed in recent days, despite the project having been in production for multiple years. It had, however, been the subject of rampant speculation among Swifties in recent months, something that Swift fuelled when she posted a cryptic countdown on her website in May.

Now, Thomas Jordan, who worked as a VFX supervisor on the film, has revealed that even many of those working on the film did not know that Swift had contributed a song.

Speaking at a SXSW London panel, he said only “a very small group” knew about ‘I Knew It, I Knew You’, with Disney and Pixar showing press and staffers a version of the finished film without the song.

“The crew that made Toy Story 5 did not know about this secret until last week,” Jordan said (via Variety), explaining that a “decoy version” was used in early previews.

“Turns out, Taylor Swift is a huge Toy Story fan like many of us,” Jordan added. “She actually saw an early version of the film, she requested to see it before it was finished and she wrote the song and then asked us if we wanted it. And we said, ‘Uh, yes! Yes we do.’ That was in February, so we’ve had to keep it a secret ever since then.”

After the song was finally announced, Swift wrote: “I’ve always dreamed of getting to write for these characters who I’ve adored since I was a five year old kid watching the first Toy Story movie. I fell instantly in love with Toy Story 5 when I was lucky enough to see it in its early stages, and I wrote this song as soon as I got home from the screening. Sometimes you just know, right?”

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She added a video of herself as a child dressed as Jessie, noting: “Writing this song felt like a musical departure and coming home at the same time.

“Creating something for Jessie was a new challenge and also felt like second nature all at once. And being a @toystory kid from the age of five til now… is an adventure I plan to be on, to infinity and beyond.”

The film will pick up after Woody left to stay with Bo Peep at the end of the last movie. Jessie is now the leader of Bonnie’s room, with Buzz Lightyear her second-in-command, but Bonnie is now enamoured with her new favourite toy, a frog-like tablet named Lilypad.

Bad Bunny is another music superstar involved in the project, after it was recently revealed that he will be the voice of a talking pizza slice, ‘Pizza With Sunglasses’, who is described as a forgotten toy living in an abandoned backyard shed.