Jackson's This Is It tour at the O2 had been due to start on July 13 but he died just weeks before his much-awaited comeback tour. Houston was one of the best selling acts through the 1980s and 1990s, courtesy her soul pedigree and powerful voice.
However her career plunged after she became addicted to a cocktail of drugs along with her husband Bobby Brown, whom she eventually separated from in 2006.
Williams has also had a similarly troubled past. By far the most successful breakout solo act from Take That, who went on to produce a string of popular albums over the past two years, his career has been dominated by mixed reviews and an ongoing contractual dispute with his record company EMI.