One lucky Cannes Film Festival-goer will get to go into outer space with Leonardo DiCaprio. Page Six has exclusively learned one of the auction prizes at tonight’s amfAR gala at Cannes will be a trip on Virgin Galactic’s space flight with “The Great Gatsby” star. Seats on the world’s first commercial space flight cost $200,000, but sources say this auction item was “priceless” because the highest bidder will be personally escorted by DiCaprio. Virgin boss Sir Richard Branson said he hopes to launch the first manned flight from his spaceport in New Mexico around Christmas this year. The ship will carry six passengers and two pilots at a time and soar to an altitude of 360,000 feet above the earth. The trip into space and back will last around 2 1/2 hours, and passengers must first go through three days of training. According to Virgin Galactic, 65,000 people have already put their names down on the waiting list for seats on the flights and celebrities reported to have bought tickets include Brad Pitt and Angelina Jolie, scientist Stephen Hawking and Ashton Kutcher. Expected guests at tonight’s 20th anniversary amfAR bash at the Hotel du Cap, chaired by Harvey Weinstein and Kenneth Cole, include Nicole Kidman, Christoph Waltz, Jeremy Renner, Rosario Dawson, Jessica Chastain, Karolina Kurkova and Janet Jackson, with performances planned by Duran Duran, Shirley Bassey and Ellie Goulding.