VIDEO : Madonna Makes Surprise Appearance At DiCaprio's Charity Auction

The Leonardo DiCaprio Foundation hosted its annual fundraising gala in St. Tropez on Wednesday night and Madonna gave a surprise performance at the event. The 58-year-old singer shared a video on Instagram of herself singing "4 Minutes" in a feathery suit. She captioned the video, writing, "Such an honor to be here supporting Leo's foundation and doing what we can to save Planet Earth!" Proceeds for the event go toward DiCaprio's Foundation, which funds environmental causes.