Keith Urban has credited his wife Nicole Kidman with improving his songwriting - because their relationship has a "profound" effect on his music.
The couple married in 2006 and two years later they welcomed their first child together, daughter Sunday Rose.
Urban admits his love for the Hollywood actress is clear in his music, and reveals his track My Heart Is Open, from his 2009 album Defying Gravity, is based on a poignant conversation between the pair.
He tells PEOPLE Country magazine, "It's been a profound impact (on my songwriting), to meet somebody who offered me a life and helped me become the person I wanted to be. (For instance) my wife and I had been out a couple of times and I wondered how she felt about me. It came out as, 'How is your heart?' She said, 'It's open.' My God, what a beautiful answer."