Sting, Elton John, Lady Gaga and Dame Shirley Bassey will perform together at Carnegie Hall, as part of the semi-annual Rainforest Fund benefit concert on May 13. The event will mark the 21st birthday of the charitable organization founded by Sting and Trudie Styler to help protect and preserve the world’s threatened rainforest areas. The performers, plus additional surprise guests, will attend a live auction and gala dinner following the concert