Taylor Swift surprises fans at 'Toy Story 5' world premiere

PHILADELPHIA (WPVI) -- The world premiere of 'Toy Story 5' took place in Los Angeles Tuesday night, and you could probably hear the screams all the way from here as Berks County native Taylor Swift surprised the crowd on the red carpet and on stage with a performance of the song she wrote for the film.

"Sometimes when you look back on your childhood, those memories, that's special in itself," said Swift.

The global superstar took to the stage at the world premiere, on the piano, with the song she wrote for the film called "I Knew It, I Knew You."

"It means so much to me to actually be a part of this film in some small way," says Swift. "It's just such an incredible world of imagination."

It turns out, the creative minds behind the scenes of this storied franchise are Swifties!

"The day we hung out with Taylor Swift was weird," laughs co-director Kenna Harris.

"We are huge fans, obviously," adds producer Lindsey Collins. "So, the fact that this actually happened and came together the way that it did, it was like the ultimate aligning of the stars."

This collaboration was also kept hidden from the stars of the film, including Tom Hanks and Tim Allen, who have been the iconic voices of Woody and Buzz Lightyear for more than 30 years now.

"The biggest secret was this Taylor Swift song at the end," says Hanks. "Which we just found out about, like, two hours ago."

This song is for the cowgirl toy Jessie, who takes the lead in this film.

"We're in our Jessie era," says Joan Cusack, the voice of Jessie. "Finally!"

The song celebrates the person who's always there when you need them most.

"It just felt like she got the voice of Jessie," says Collins of Swift. "She understood it. She understood all of it."

Swift also performed an epic duet of "You've Got a Friend in Me" with "Toy Story's" legendary singer-songwriter Randy Newman.

"It's raised so many kids, just like me," Swift says. "I watched 'Toy Story' when I was five, and I've watched every single one of the films so many times. To be able to be welcomed into something that has welcomed me unknowingly its entire existence, just as a fan, feels like very poignant for me and for my family."

"Toy Story 5" is in theaters June 19.

The Walt Disney Company is the parent company of this ABC station.