The 'Be The One' hitmaker teamed up with the Coldplay frontman on the track after her management sent an email to him and he agreed to get into the studio with the pop beauty in Malibu.
Speaking to NME magazine, the 21 year old said: "At first, it was just meant to be me singing but I begged him to sing too.
"I was like 'you have to be on this song!' and he agreed. It's the most beautiful song on the album.
"I think it really brings everyone in for a little cry."
The brunette beauty instantly got on a plane to California after Chris suggested they should write something for her self-titled debut album, which drops on June 2.
She said: "He's listening attentively and wants to know the meaning behind the songs.
"Then he's like 'OK why don't we try something for your album?'
"He sets up the mics and we're just humming ideas, making up melodies and recording it all.
"It was already quite so he gave me what we'd recorded and said 'have a listen back. If you think there's something good there, we'll come back to it'."
Dua initially thought the two would never see each other again after spending time recording, but Chris got her back over to finish the song in person.
The 'Hotter Than Hell' star said: "I had this realisation 'this is the guy you went to see at Glastonbury'.
"And at that point I was like 'Oh my God. What's happening to me? This is just crazy'."
Dua's album also features her collaboration with Miguel, 'Lost In Your Light'.
She has previously worked with Sean Paul on their track 'No Lie'.