Pop star Janet Jackson celebrated her 40th birthday with celebrity friends at Hollywood hotspot Shag on Tuesday night (16MAY06). Among the guests were Jackson's boyfriend Jermaine Dupri, rapper Busta Rhymes and PARIS and Nicky Hilton. The star was serenaded by Stevie Wonder, who sang a special rendition of HAPPY BIRTHDAY. The CONTROL singer has recently unveiled a sleek new look for the upcoming release of her new album 20 YEARS OLD.