In 2011, the two got involved in a Twitter feud after he canceled plans to open for the singer on tour at the last minute. The two later reconciled and even collaborated on new music. Earlier this year, Harris released a new single, "Feels," which featured Perry, as well as Big Sean and Pharrell Williams.
"I saw Calvin actually at [the] Vanity Fair Oscar party. We just bumped into each other and he's like, 'Oh, you know, it's so funny, I think I have a song that maybe you should come check out,'" Perry said in an interview on Ryan Seacrest's KIIS-FM radio show On-Air With Ryan Seacrest Wednesday. "I was like, 'Cool,' because we'd always meant to work together for years and years and years."
"We'd had little falling outs here and there," she added. "We'd had some public Twitter spats and it was like, eight years or so had passed. It was time to put all that behind us. Then he played me this one part for this new song called ‘Feels' and I was like, ‘Oh yeah.' This is like my favorite song off the record. I was just down to do it."