Andrea Bocelli had planned to duet with a "young female pop star" on 'Fall On Me'.
The 60-year-old Italian tenor did a demo of the song - which became the soundtrack to Disney's 'The Nutcracker and the Four Realms' - with his 19-year-old son Matteo, but producer Bob Ezrin has revealed it was intended that the recorded album version would feature a woman's vocals.
Keeping the pop star's name tight-lipped, the studio wizard told Billboard: "When we were gathering out thoughts about what it ought to be, I spent some time with Andrea and his son, Matteo, and the rest of his family. They sent me the song 'Fall on Me' as a potential duet between - I'm not gonna say the name - but (Bocelli) and a very important young female pop star. But the demo they sent me, which was in English, was sung by his son Matteo."
However, Bob suggested a change in the story to make the relationship about a father and son, and so Matteo ended up on the track in the end.
He explained: "It was written as a conversation between two young people who were uncertain of love and looking to each other for support; I thought with a very, very small adjustments this could easily be a conversation between a father and a son who is unsure of love and life and doesn't know his position in the world who suddenly hears the voice of his father come to him from afar, and the wisdom of the father and the love of the father would come to him and help guide him.
"Even as I was thinking about it I was getting goosebumps, 'cause to me that was a unique and honestly emotional interpretation of the song, whereas having a love song between two people who aren't really in love ... those work all the time, but they're constructs.
"I thought we could do something that was more of a truth, especially with a man who is so devoted to his family and a family that's so warm and full of love. So I asked if we could just do a duet with the two of them."
Though it's not known who the original singer for 'Fall On Me' was, Dua Lipa recorded the English version of 'If Only' on Andrea's album, 'Si', which recently topped the charts in the UK and US.
Complimenting the 'Electricity' hitmaker, Bob said: "She's just magic. When they said Dua was interested in doing the duet, I was so excited about it.
"I love the vocal she did, and the vocal she did fell in so natural and sounded so in keeping with the rest of the piece.
"It was almost as if it was meant to be."