Dj Cassidy was determined to work with Jessie J on his debut single 'Calling All Hearts' - which also features Robin Thicke and Nile Rodgers - because of her ''electric'' personality and ''powerful'' voice.
The DJ-and-producer has recruited a number of stars for his debut album 'Paradise Royale', including R. Kelly and John Legend, but he was desperate to get Jessie to provide vocals on 'Calling All Hearts' after being introduced to her by songwriter Claude Kelley.
He exclusively told BANG Showbiz: ''Claude obviously has worked with Jessie his whole career and had many number one records with her.
''He always said to me, 'We need to get Jessie,' and he was dead on. Her voice is so uniquely powerful and uniquely soulful and her personality is just electric and she just lifted this song up.''
Cassidy finally got to pitch his idea to Jessie, whilst she was eating a sandwich during a break in the recording sessions for her last album 'Alive'.
He said: ''When she came to New York to finish her album with Claude, Claude said come to the studio, we're having lunch, it's the perfect time to pitch. I ran to the studio and whilst she was eating her sandwich, I pitched her the project.''
Jessie was so excited by the track - which also has Nile Rodgers on guitar - that she insisted they record it straight away.
Cassidy - who has deejayed for some of the world's most famous and important people, including President Barack Obama, Jennifer Lopez and at the wedding of Jay Z and Beyonce - added: ''I played her the demo of 'Calling All Hearts' and she said, 'I want to record it right now. Two hours later, the song was done.''
'Calling All Hearts' also features Robin Thicke on vocals and the 'Blurred Lines' hitmaker was just as keen as Jessie to get on board with the project once he heard the song.
Cassidy revealed: ''I'm playing Andre Harrell, legendary R&B mogul, my album and he says, 'How come Robin's not on this f***ing album?'. And I said, 'Well, I first played some tracks for Robin when I started and he had sketched out some things which never panned out.' He said, 'I'm calling Robin right now; he happens to be in New York.' So he calls Robin and at one in the morning I go to the hotel and I play Robin my album. I get about halfway through before I play 'Calling All Hearts', after one verse, he stops it and says, 'I'm recording this song with her.' Next day, he flew to LA and recorded the song.''
'Calling All Hearts' is available to download from this Sunday (20.04.14).
The movie begins filming in the UK.