Taylor Swift changes into a plunging yellow gown as she performs unexpected duet of You've Got A Friend In Me with Randy Newman at Toy Story 5 premiere

Taylor Swift stole the show at the Toy Story 5 premiere at LA's Dolby Theatre on Tuesday.

The Pixar sequel features a new original track from the singer, titled I Knew It, I Knew You, which has already smashed streaming records.

After making a surprise appearance on the red carpet, Taylor, 36, changed out of her pretty Erdem ensemble into a plunging yellow gown to take to the stage for her first live performance of the track. 

There was another surprise in store though as Taylor then introduced legendary singer/songwriter Randy Newman.

'I am lucky enough to be here because of someone else who is the architect of the Toy Story musical universe,' she told the crowd.

'He is the king of making us feel the absolute most and pulling at our heartstrings and making us laugh and making us like he’s one of our friends, you know what I mean. I’m talking about Randy Newman.'

Randy then appeared on stage, seated at a piano before the two launched into a duet of You've Got A Friend In Me, the track which was used as the main theme song for the first Toy Story film in 1995.

Taylor has penned a new track for the fifth installment, which Disney describes as 'a return to Taylor Swift's country roots', and draws inspiration from Jessie's storyline in the franchise.

The track was crafted with the help of Taylor's longtime collaborator Jack Antonoff.

On stage Taylor praised Joan Cusack for having done 'an extraordinary job' voicing Jessie, and added, 'It was an honor to write for her, and I am very lucky that I got to write for this film.'

Elsewhere at the premiere Taylor couldn't contain her smile as she got her childhood VHS tape of Toy Story signed by Tom Hanks and Tim Allen. 

The pop megastar beamed as Tom, 69, and Tim, 72, who voice Woody and Buzz Lightyear in the iconic Disney film, signed the 1995 VHS in a sweet moment on the red carpet. 

Tim penned his character Buzz Lightyear's famous phrase: 'To infinity and beyond' and added his signature, while it is unknown what Tom wrote on the vintage 30 year old tape. 

Taylor stole the spotlight on the red carpet in a leggy off-the-shoulder embellished dress by Erdem.

She completed the look with a necklace with a diamond horseshoe pendant, a nod to the film's cowgirl Jessie.