Katy Perry and Zedd are working on a song together.

The chart-topping DJ - who has worked with the likes of Liam Payne, Alessia Cara and Maren Morris - has revealed the pair have been in the studio whilst he's supporting the 'Part of Me' hitmaker on the Australian and New Zealand leg of her 'Witness World Tour'.

However, the 'Middle' hitmaker has no idea whether their song will make the final tracklisting of the pop star's follow-up to 2017's 'Witness'.

The EDM star told Australian radio presenter Smallzy in a video interview posted on his Twitter account: ''I'm always relatively open about the fact that I make a lot of music with people.

''It doesn't always come out, but we've been working. I always wanted to release a song with her, so if we all get lucky, then maybe we'll finish the song and it will come out.''

The news Katy and Zedd are working together comes after Katy recently admitted she has suffered from ''bouts of situational depression''.

The 'Dark Horse hitmaker admitted her ''heart was broken'' last year when there was a mixed response from the public to 'Witness' and she has been working hard to improve herself.

She said: ''I had bouts of situational depression. My heart was broken last year because, unknowingly, I put so much validity in the reaction of the public, and the public didn't react in the way I had expected to. Which broke my heart.''

The 33-year-old singer decided to go to the Hoffman Institute in California to give her ''a new foundation.''

She added: ''For years, my friends would go and come back completely rejuvenated, and I wanted to go, too. I was ready to let go of anything that was holding me back from being my ultimate self. Music is my first love and I think it was the universe saying, 'OK, you speak all of this language about self-love and authenticity, but we are going to put you through another test and take away any kind of validating 'blankie.' Then we'll see how much you do truly love yourself.' That brokenness, plus me opening up to a greater, higher power and reconnecting with divinity, gave me a wholeness I never had.

''I recommend it to everyone, my good friends and other artists who are looking for a breakthrough. There are a lot of people who are self-medicating through validation in audiences, through substances, through continually running away from their realities - denial, withdrawal. I did that for a long, long time too ... The biggest lie that we've ever been sold is that we as artists have to stay in pain to create.''