According the reports in Sydney, Australia's The Daily Telegraph newspaper, Urban opened his heart to the Moulin Rouge! beauty during a touching rendition of the BROOKS + DUNN song BRAND NEW MAN.
The track is an emotional story about a down and out drug addict whose life is transformed when he falls in love with the woman of his dreams.
With Kidman listening attentively, Urban crooned, "I used to love 'em and leave 'em, I'd brag about my freedom... then I met you, now my heart beats true. Baby you and me together, feels more like forever."
The celebrity couple have remained tight-lipped about their relationship ever since rumours of romance surfaced last year (05).