Charli Xcx and Iggy Azalea's hit single Fancy was written in just 30 minutes.

The British singer-songwriter has revealed it took her and Australian-born rapper Iggy less than an hour to bash out the lyrics for their catchy track. Fancy was the fourth release from Iggy's 2014 debut album The New Classic, released by Def Jam Recordings.

The song reached number one on the Billboard Hot 100 and held the spot for seven consecutive weeks. It also topped the charts in Canada and New Zealand and reached the top 10 in several countries including Iggy's native Australia and the United Kingdom.

In an interview with People magazine, Charli - real name Charlotte Emma Aitchison - shared: "We wrote it in like half an hour. Iggy had like done her rap so I just came in the studio and put the chorus down so that was it, it was a really quick process."

It was the second number one hit for the British artist who topped the UK charts with song I Love It, a collaboration with band Icona Pop, and proved to be life-changing.

"I think really behind the scenes, (more) than my life. It did change my life in the sense that, I was definitely exposed to a lot more people, you know I was writing with bigger artists, and I guess I just partied a lot more after 'Fancy', which was really cool," she smiled.

The Boom Clap hitmaker also took the time to name-check Selena Gomez as being great to work with on song Same Old Love.

"We hung out in London after she cut that song, I really respect her a lot, she works really hard, she's a cool girl," she recalled of working with the pop artist.

And Charli enjoys a close bond with Rita Ora dubbing the Kosovo-born British singer as her "only famous friend".