After touring Latin America in late 2004 for the promotion of his Greatest Hits album, Williams started working on what would become his sixth studio album. Recorded in his bedroom in the Hollywood Hills, the album was co-written by Stephen Duffy over the course of 24 months. The album was launched in Berlin, Germany on 9 October 2005. It was not shown on television, but broadcast to various locations around the world in cinemas and theatres, in a high-definition "cine-cast". It was shown on Saturday 22 October 2005 on Channel 4.
When Intensive Care was released in October 2005, it became a smash hit around the world, hitting number-one in the United Kingdom, selling 373,832 copies in its first week, as well as topping charts in twenty other counties including Argentina, Australia, Austria, Germany, Sweden, Switzerland, The Netherlands, New Zealand and many other countries. Following the success of the album, Williams won the MTV Europe Music Award for 'Best Male', and also entered The Guinness Book of World Records for selling 1.6 million tickets in a single day for his 2006 world tour. The album became the best selling album in Europe by the end of 2005, with sales of over four million copies. However, it only managed to become the third best selling album in the United Kingdom that year. Williams kicked off his Close Encounters World Tour in South Africa in April 2006 in promotion of the album. More than 2.5 million attended the early stages of the tour, with nearly three million having been reported to have seen one or more shows. In January 2007, it was revealed Intensive Care had sold over 5 million copies in Europe, and as such, was certified 5× Platinum by the IFPI. It was also certified 5× Platinum in the United Kingdom around the same time. In Mexico, the album was certified platinum shortly after its release, for shipping 150,000 copies of the physical album, and in December 2008 the album was certified 2× diamond for pre-loaded digital sales of 1,000,000 copies. By shipping 1,100,000 copies and reaching 11× gold,Intensive Care became the eighth best-selling album of the decade in Germany. It also became Williams' fifth album to reach a position in the top twenty of the best-selling album of the decade, with Swing When You're Winning, Escapology, Live at Knebworth and Greatest Hits also earning places. According to EMI, the album has sold 6.2 million copies worldwide.
"Tripping" was released as the album's lead single on 3 October 2005, becoming an international success, topping the charts in Germany, The Netherlands, Taiwan, Argentina and Mexico. In the United Kingdom, it was released as a double A-side with "Make Me Pure", however, "Make Me Pure" was also released separately in Australia, New Zealand and Mexico.
"Advertising Space" was released as the album's second single in December 2005, becoming another international hit, reaching the top ten in Europe, Australasia and Latin America.
"Sin Sin Sin" was released as the album's third and final single in the summer of 2006. It was the first song Williams and Stephen Duffy co-wrote together. The video was shot in Cape Town, South Africa just days before the start of Williams' tour there. It became Williams' first single to miss the UK Top 20, charting at number twenty-two, however, it performed much better internationally, hitting the top ten in Europe and Latin America.