Almost 20 years ago, Kate Winslet and Leonardo DiCaprio starred together in the film Titanic. They played the movie’s two lovers, Rose and Jack. Ten years later, they appeared together in the 2008 film “Revolutionary Road.” This week, Winslet and DiCaprio are coming together again. But it is not for a film. It is for a dinner. And one lucky fan will get to join them. The prize of a private dinner is part of the yearly fundraising event for the Leonardo DiCaprio Foundation. The organization gives money to environmental causes.