Pop superstar Taylor Swift has premiered her Eras Tour concert film in front of fans and celebrities after announcing the movie will debut a day early because of “unprecedented” ticket demand.

Taylor Swift: The Eras Tour had been scheduled in theatres worldwide on Friday, but high interest prompted Swift to add earlier screenings in some markets.

“Look what you genuinely made me do: Due to unprecedented demand we’re opening up early access showings of The Eras Tour Concert Film on THURSDAY in America and Canada!!” the Anti-Hero singer wrote on social media.

Additional showtimes were also being added for the weekend, Swift said.

Later, Swift stepped onto a red carpet in a strapless pale blue gown for the film’s world premiere.

She posed for selfies with fans who scored a seat in one of 13 auditoriums in an AMC Theatre at an outdoor mall in Los Angeles.

Scattered in the crowd were celebrities including comedian Adam Sandler, Law & Order actor Mariska Hargitay and Barbie star Simu Liu, who was wearing friendship bracelets on his wrist like many of Swift’s fans.

‘This much fun’

Inside the theatre, Swift thanked fans for supporting the Eras Tour, which has sold out stadiums around the world.

She applauded “the amount of care and preparation and passion that you put in, the intensity that you put into coming to these shows”.

“I’ve never had this much fun in my life as I had at the Eras Tour,” she said.

Ticket sales for Swift’s movie, which is being distributed by AMC Theatres, are expected to set records for a concert film, and industry analysts have been upping their forecasts.

Box Office Pro projects the movie will take in between $US105 million ($164 million) and $US140 million ($218 million) in the US and Canada across its opening weekend.

Taylor Swift: The Eras Tour begins screening in Australian cinemas on Friday.

-AAP