After finishing Showgirl: The Homecoming Tour in early 2007, she returned to the studio to complete the album, with the help from many producers including Bloodshy & Avant, Calvin Harris, Greg Kurstin, and Freemasons.

[5] She canceled the remaining concert dates and underwent immediate treatment: she had a partial mastectomy to remove a lump from her left breast and spent the next six months receiving chemotherapy.

[14] Towards the end of her cancer treatment in mid-2006, Minogue began writing in Melbourne, including the lyrics that would later form the basis of "Cosmic" and "No More Rain".

[21] Danish producers Cutfather and Jonas Jeberg forwarded a demo of "Like a Drug" to Parlophone and later flew to London to record the track with Minogue within a day.

[20] Sessions in Stockholm with songwriter Poole and Swedish producers Bloodshy & Avant resulted in the tracks "Speakerphone", "Cherry Bomb" and "Nu-di-ty".

[42] English band Hot Chip was asked to meet a "top-line songwriter" from Minogue's camp, but this never occurred as they were busy making Made in the Dark (2008).

[44] Further submissions came from Boy George,[45] Amanda Ghost,[45] Mark Ronson,[46] Daft Punk,[46] Alan Braxe,[46] Groove Armada,[46] Hannah Robinson,[47] Siobhan Fahey,[37] Goldfrapp,[37] Dragonette,[44] Sneaky Sound System,[48] and Kiki Lesendrić.

[52] Tom Ewing of Pitchfork called it an album that "hops around searching for a sound it's comfortable with" and felt Minogue was trying to have "the whole contemporary UK pop scene on a single CD".

Music, Alexis Petridis of The Guardian and Ewing found the influences from other contemporary artists in the late 2000s, such as Daft Punk, Girls Aloud, Britney Spears, Gwen Stefani and Sugababes.

[62] Ewing wrote the track swings harder than anything else on the album, while Spike commented it comes off like a diluted version of "Cowboy Style" (1997) with a slower pace.

[65] Ewing felt his production works like "a cassette player version of Justice—all hiss and stickytape", while Ed Power of Hot Press called it a Giorgio Moroder update for the Generation Z.

[69] Both Ewing and Bruce Scott of Prefix commented that "Heart Beat Rock" is better suited for Gwen Stefani, who embodied a more sassy and exciting tone.

[79] Hughes claimed "Speakerphone" flirts with hip hop elements, while Levine and Dan Weiss of Lost At Sea viewed the track as an extension of Spears' Blackout era.

[93] About.com's Jax Spike viewed it is "an album meant for partying and having fun", while Petridis noted it relies heavily on the sexual and filled with double-entendres.

Josh Love of The News & Observer thought her voice can match with the "chirpy buoyancy" of Stefani, Spears and Janet Jackson.

[104] Sawdey, on the other hand, found Minogue engages the listener with her sex kitten persona despite her limited voice, and compared her robotic delivery on "Speakerphone" favourably to those of Spears during her Blackout (2007) album.

[113] After the release of X was announced with a confirmed tracklist on 21 September 2007, Mylo briefly posted two of his rejected tracks for the album on his official website and MySpace account.

[121] A limited USB edition was available in the UK and Canada, featuring a tiny animated doll of Minogue in the style of the release artwork.

[126] In the United States, Capitol and Astralwerks released X in April 2008 with two bonus tracks: the extended mix of "All I See" featuring rapper Mims and "Carried Away".

[128] A special tour edition package was released in southern Asia and Australia, featuring the track "Magnetic Electric", various remixes and bonus videos.

[135] On 1 April, the same day X hit US stores, Minogue performed "All I See" and "Can't Get You Out of My Head" live on a season 6 episode of the American program Dancing with the Stars.

[142] The concerts were divided into eight segments: Xlectro Static, Cheer Squad, Beach Party, Xposed, Naughty Manga Girl, Starry Nights, Black Versus White, and the encore.

[162] Ben Ib directed the music video in a green screen studio in the Manchester Evening News Arena, influenced by images of Carol Lombard and Lauren Bacall.

[165] A version of "Sensitized" featuring French singer Christophe Willem served as a promotional single in Europe, but did not appear on any major record charts.

[52] Writing for The Village Voice, Hunter considered Minogue as the main factor that makes X great, who "has an ear for fantastic pop-rock tunes restyled for 2008, and she approaches them as totally vital music".

Petridis dismissed the generic themes, and commented Minogue's voice through effects sounds like "a 13-year-old boy has somehow wrested control of Stephen Hawking's computer".

[176] Barry Walters of Spin and Nick Levine of Digital Spy viewed X as a catchy set of songs, and an opportunity for her to express her feelings, but Minogue refused to give anything away.

[179] Writing for Slant Magazine, Dave Hughes argued the hit-or-miss production gives X the "focus-grouped attention deficit disorder" of a Gwen Stefani record.

[182] At the 22nd ARIA Music Awards, X garnered two nominations for Best Female Artist and Best Pop Release, ultimately losing both to Gabriella Cilmi's Lessons to Be Learned (2008).

[188] The album spent 14 weeks in the top 50,[188] ultimately earning a platinum certification from the Australian Recording Industry Association (ARIA) within the year, for shipments over 70,000 copies.