Katy Perry supports Taylor Swift at Eras Tour concert and sings along to 'Bad Blood'

Katy Perry supported her friend Taylor Swift at Swift's Eras Tour stop in Sydney on Friday night.

The "American Idol" judge and singer shared a series of photos and videos from the concert having the time of her life.

"Got to see an old friend shine tonight ♥️✨," Perry wrote in the caption of the post.

In the first image, Perry shared a selfie of her and Swift smiling. Another image shows the moment a fan gave Perry a friendship bracelet.

Perry also shared photos of herself getting ready for the concert and a photo of her and singer Rita Ora, as well as a video of her and Ora singing along to "You Belong with Me."

The final video Perry shared in her post was of her singing along to Swift's song "Bad Blood."

Perry and Swift appeared to mend their friendship back in 2018 after a longstanding feud that began in late 2013. Neither officially commented at that time on what had caused the rift, but a popular theory among fans was that it stemmed from dancers leaving Swift's tour to join Perry's.

Swift told Rolling Stone magazine in 2014 that the song "Bad Blood" was about another female artist, but didn't name names.

"For years, I was never sure if we were friends or not," Swift said. "She did something so horrible. I was like, 'Oh, we're straight-up enemies.' And it wasn't even about a guy! It had to do with business. She basically tried to sabotage an entire arena tour. She tried to hire a bunch of people out from under me."

The caption of Perry's Instagram post on Friday refers to the note she sent Swift in 2018 along with an olive branch. The note, which Swift shared on Instagram at the time, read in part, "Hey old friend, I've been doing some reflecting on past miscommunications and hurt feelings between us. I really want to clear the air."

Following the olive branch post, Perry took to Instagram in 2019 to share a photo of a plate of cookies with the words, "PEACE AT LAST" written in icing. She captioned the post, "feels good 🧡@taylorswift."

Swift is currently in Australia for the international leg of her Eras Tour. She recently wrapped three shows in Melbourne, and has several shows scheduled at Accor Stadium in Sydney, before heading next to Singapore.