Beyoncé, Rachel Zegler and Adam Sandler were among the stars attending the world premiere of Taylor Swift: The Eras Tour in Los Angeles on Wednesday.
Swift, wearing an Oscar de la Renta full-length blue gown, posed with her fans and fellow celebrities on the red carpet.
"I've always had fun doing this. I can't believe I get to do music as a career. That's crazy," she said.
The Eras tour was "the most electric experience" of her career, she added.
"I've never had this much fun in my life as I have had on The Eras Tour.
"We did this show rain or shine, in sickness and in health, no matter what was going on in our lives. And we did it with a grin on our face because what greeted us on the other side."
The film was recorded during the US leg of her Eras Tour and the set list includes tracks spanning her whole career.
However, the sprawling, four-hour show has been edited for the cinema, with fan favourite tracks like Wildest Dreams, The Archer and Cardigan missing from the running order.
It will be released in the UK on Friday, but Swift has announced last-minute "early access screenings" for fans in the US, due to "unprecedented demand".
Details ahead of Wednesday's premiere were shrouded in secrecy, with select fans receiving invitation-only tickets for opening night via Spotify.
The venue - a 14-screen cinema in an upmarket shopping centre in Hollywood - was completely closed down to accommodate the throngs of fans.
With hours to go, it was still not confirmed whether Swift would be in attendance, but fans erupted as the star appeared just moments before the action began.
The movie, which was filmed over the course of three concerts in Los Angeles' SoFi Stadium in August, has already made more than $100m (£83.2m) in advance global ticket sales.
That makes it the biggest concert film of all time, overtaking Justin Bieber's Never Say Never, which made made $99m (£80.5m) in 2011.