Sue Barker is at Wimbledon for live coverage of a moment of history at the world's most famous tennis court - the first match to be played under Centre Court's new roof. The retractable roof will be used at 2009's Championships and a star-studded line-up will be taking part in this specially arranged test event. Steffi Graf, a seven-time singles champion at the All England Club, will be returning to grace Centre Court for the first time since 1999, along with fellow tennis legend - and husband - Andre Agassi, who was himself the men's singles champion in 1992. Also in action will be Tim Henman, Britain's most successful player at Wimbledon in the modern era and a man who could have done with the roof when his 2001 semi-final with Goran Ivanisevic was halted by rain at crucial points in the closing stages of the match. The ever-popular Kim Clijsters, who has recently announced that she will be coming out of retirement and returning to the tennis circuit later in 2009, will also be playing. Commentary comes from Andrew Castle and John Lloyd.