Today, the pop superstar announced on Twitter that special disco balls had been placed in various locations across the world.
If fans found the disco balls, they could listen to the song two days before its release.
Chained To The Rhythm is available to everyone on 10 February.
Newsbeat spoke to Katy Perry fans in London's Leicester Square, the only UK location of a Katy's disco ball, to find out what they thought of the first song from her fifth studio album.
Carrie, 16, tells Newsbeat she has been a fan since she was nine and first heard Katy's breakthrough hit, I Kissed A Girl.
"Chained To The Rhythm is just so good. It's so catchy," she says.
"I can't wait for everyone else to hear it. You're going to want to dance and go crazy to it. It's been worth the wait definitely."
Samson, 22, has been a fan since Katy's second album, Teenage Dream. He loves the new track and the stunt to help fans hear the song early.
"It's very catchy and hopefully it will be a hit I think. I like it, I think it's good," he tells Newsbeat.
"I think this is the best promotion ever. As a fan you obviously want to listen to it before it's released and it's great fans can come together and listen to the song."
Adam, 19, raced to Leicester Square after finishing a lecture at university and he loves the song too.
"It is a bop, it's a real bop," he says.
"It's like bringing back old Katy Perry vibes, back to the Teenage Dream times. I can't imagine how good it's going to sound live on tour."
Naticka, 20, says she loves Katy Perry so much that if The Hunger Games was real, she'd volunteer to take Katy's place in the competition should the situation arise.
"It's quite dancey but it's quite chill-out at the same time," she says of the new song.
"I definitely think it's going to be number one."
Australian Nick, 21, was Snapchatting friends back home when he got to the Katy Perry glitter ball hours before fans back home got the chance to listen.
"You can tell Sia wrote it," he says.
"It's pretty disco-y, it's 80s but not annoyingly so. I'd call it a pop gem, it's like a crystal, I love it."
The locations included are mostly in America and Europe and fans found glitter balls chained to benches in the places indicated on the map. Perry had previously teased the song with a short video clip.
The song was named after several days of rumour, following confirmation that she would perform at the 2017 Grammy Awards.
Earlier this week she retweeted an announcement about her performance at this year's Grammys and updated her social media channels with a new promo photo. Chained To The Rhythm is the first single from Katy's fifth studio album, following her 2013 release Prism.