Katy Perry joined Zedd on stage at Coachella on Sunday (14.04.19).

The pop superstar teamed up with the chart-topping German-Russian DJ for a rendition of their hit song '365' during his set at the Empire Polo Club ground in Indio, California.

The 'Chained to the Rhythm' hitmaker had already teased her appearance at the famous festival by taking to Twitter to advise her 107 million followers to check the live stream of Coachella after tuning in to watch her on 'American Idol'.

She wrote: ''After you're done watching Idol, East Coast (and before yours begins, West Coast), you might want to check out the Coachella live stream... around 7:30pm poss? http://YouTube.com/Coachella - Channel #GetYouAGirlWhoCanDoBoth (sic)''

The 'Teenage Dream' hitmaker attended the festival with her fiancé Orlando Bloom and the pair both shared posts about watching Billie Eilish the day before (13.04.19).

After her set, the 'Pirates of the Caribbean' star wrote on Instagram: ''Verified

occasionally the most authentic of humans comes along and scoops up all the heart n minds and makes a grown man gush still tripping over last nights set @wherearetheavocado (sic)''

Katy also took to the social media app to share backstage snaps with the 17-year-old pop sensation and Orlando, 42, and admitted the 'Bury A Friend' hitmaker needs to be protected as she is one of a kind.

She captioned the post: ''we must protect @wherearetheavocados, beings like her don't enter our orbit often (sic)''

Meanwhile, the 34-year-old singer had admitted that she felt old amongst the young crowd at the festival.

She tweeted: ''feel like I've been doing full looks at @Coachella for as long as some of these people have been alive (sic)''