Nightlife is the seventh studio album by English synthpop duo Pet Shop Boys, released on 8 October 1999 by Parlophone. After the release and promotion of their previous album, Bilingual, Pet Shop Boys started work with playwright Jonathan Harvey on the stage musical that eventually became Closer to Heaven (at one stage during the writing process, the musical was given the name of Nightlife). Pet Shop Boys soon had an album's worth of tracks and decided to release the album Nightlife as a concept album and in order to showcase some of the songs that would eventually make it into the musical.
"In Denial" is a duet featuring Kylie Minogue. It was seen as a risk by critics because this project came at a time when Minogue was experiencing low record sales and did not have her own record contract. Pet Shop Boys had previously written a song titled "Falling" for Minogue's 1994 album Kylie Minogue. The year after Nightlife's release, Minogue also signed to Parlophone and released her hugely successful Light Years album in 2000. Minogue would later sing "In Denial" on her Showgirl: The Greatest Hits Tour, with Tennant's pre-recorded vocals being played as part of the duet while Minogue sang live.
For the promotion of the album, the band adopted a stark new appearance, designed in consultation with theatre designer Ian McNeil. Now, the duo ubiquitously appeared wearing thick, dark eyebrows, inspired by Kabuki theatre; yellow or orange wigs in a variety of hairstyles, inspired by the punk subculture (especially several spiked wigs); and black sunglasses. This was supported by a series of outfits in dark, muted colours, the most deviant of which incorporated culottes, inspired by the attire of samurai, instead of trousers. Photographs involving the costumes were often set in urban environments; the Midland Grand Hotel in Kings Cross, London was used as the setting to debut the look. The costumes were used for promotional photographs, the album cover and liner notes, all the single covers, as well as the Nightlife Tour.
The music video for "I Don't Know What You Want But I Can't Give It Anymore" showed Tennant and Lowe being transformed into their new appearances, though in a fantastical manner: they are operated on by medical laboratory machines, then covered in talcum powder and dressed by monks in a ritual-like manner. Finally, they are given dogs on leashes and released into a "different world", where everyone else is also dressed in exactly the same way. Conceptualised among the band members, McNeil, and director Pedro Romhanyi, the video was created to showcase the costumes. It was visually influenced by the films THX 1138 (1971) in the initial transformation sequence (copying many of its shots and props precisely); Ridicule, in the ritualistic dressing-up scene; 2001: A Space Odyssey (1968), in the decor of the living room with an illuminated floor; and A Clockwork Orange (1971), in the outdoor urban setting.
According to Tennant, the costumes helped him to distance himself from the songs, adding to the impersonal nature of Nightlife. In other interviews, he explained that they played into his belief in the need for pop stars to have "bigger than life" public images, and were a reaction against the "naturalistic" look of the 1990s.
Effort was also spent on designing the tour's visuals, with sets designed by deconstructivist architect Zaha Hadid. The stage was modular, and could fit in differently-sized venues and be rearranged by the backing singers throughout each concert.
A limited edition two-CD set of Nightlife was released in the United States. The bonus disc, titled Nightlife Extra, contained all the B-sides from the UK releases of the "I Don't Know What You Want But I Can't Give It Any More" and "New York City Boy" singles, as well as remixes of these singles, some of which were only available in the US on promotional releases.