Vanessa Paradis and Johnny Depp's daughter "came up with the prettiest melody" for one of her songs.

The French singer and actress is going on tour later this year and will perform a song that her and Johnny's daughter Lily-Rose has a writing credit for. The 41-year-old revealed that her teenage daughter came up with the melody when she was only six-years-old.

"Well what happened was, Johnny had written the chords of a song and I was looking for a melody. Johnny kept playing the chords over and over, trying to find a tune," she explained to the US edition of Elle magazine. "She heard the song so many times that she finally came up with the prettiest melody for the verses by herself. She made up her own words, too, for the first part. And when I heard it, I said, 'This is so pretty, can I use it?' So that’s how the song came together."

Vanessa and Johnny split up in 2012 after 14 years together. The star is now focusing on career and will soon be seen alongside renowned director and actor Woody Allen in Fading Gigolo, her first major American film. Vanessa found Woody's style of acting an eye opening new experience.

"Filming scenes with Woody Allen was the toughest thing I had to do. He improvised really funny lines, and every day was different," she said. "My first day was shooting with him, he said, 'I hope you don’t mind, I’m improvising most of my lines', and I said, 'Oh Woody, no problem.' But it kind of was a problem, because I never knew when I had to come in! You don’t want to cut him off because he’s Woody Allen! He’s brilliant!"