The actress Trudie Styler and her husband, the pop singer Sting, will be joined by more pop stars - Paul Simon, James Taylor, Dionne Warwick, Ivy Levan - as well as a trumpeter, Chris Botti, and an opera singer, Renée Fleming, in the biennial Revlon Rainforest Fund Benefit Concert at Carnegie Hall on April 17. "This year is the Rainforest Fund’s 25th anniversary," Ms. Styler and Sting said in a statement, "and its work to protect rainforests around the globe for the people who live there and for all of us is more important than ever."