Her discography consists of one spoken word album, one extended play, three singles, three music videos, ten other appearances, a number of unreleased tracks and two tribute songs recorded by various artists.

Kidman, primarily known in the field of acting, entered the music industry in the 2000s after recording a number of tracks for the soundtrack album to Baz Luhrmann's 2001 motion picture Moulin Rouge! that she starred. Her duet with Ewan McGregor entitled "Come What May" was released as her debut and the second single of the OST through Interscope on 24 September 2001. The composition became the eighth highest selling single by an Australian artist for that year, being certified Gold by Australian Recording Industry Association, while reaching on the UK Singles Chart at number twenty-seven. In addition to, the song received a nomination at the 59th Golden Globe Awards as the Best Original Song and has been listed as the eighty-fifth within AFI's 100 Years...100 Songs by American Film Institute.

"Somethin' Stupid", a cover version of Frank and Nancy Sinatra followed soon. The track recorded as her common duet with English singer-songwriter Robbie Williams was issued on 14 December 2001, by Chrysalis as the lead of his fourth studio album Swing When You're Winning. Kidman's second single topped the official music charts in Italy, New Zealand, Portugal and England, as well as scored top ten placings all over Europe, including Australia, Austria, Belgium, Denmark, Germany, Netherlands, Norway and Switzerland. Apart from being certified either Gold or Silver in a number of countries, it was classified as the eleventh best-selling single of 2002 in Italy, thirtieth in the UK, the fifty-ninth in Australia, and the ninety-third in France, respectively.

On 5 April 2002, Kidman released through Interscope her third single, a cover of Randy Crawford's "One Day I'll Fly Away". A Tony Philips remix of the track was promoted as the pilot single of a follow-up to the original soundtrack of the same name, Moulin Rouge! Vol. 2. After that, in 2006, she contributed with her vocal for the OST Happy Feet on a rendition of Prince' "Kiss". While in 2009, she was featured on the Nine soundtrack ("Unusual Way").

Most recently, her name has been credited on a track called "What's the Procedure", issued on 14 March 2013, on the compilation I Know Why They Call It Pop: Volume 2 by Rok Lok Records. Among others, Kidman also narrated an audiobook in 2012.