by Jacki Garfinkel, Suzy Byrne and Saryn Chorney

Making a movie or TV show in Tinseltown is a lot like mating in captivity: Beautiful creatures are forced to make nice in a contrived setting for the benefit of eager, voyeuristic eyes. Indeed, some of the silver screen's most legendary couples — Humphrey Bogart and Lauren Bacall, Katharine Hepburn and Spencer Tracy — hooked up on the set of movie productions, and young Hollywood has been keeping the tradition alive and kissin'. Meet the latest batch of sweethearts (like Claire Danes and Hugh Dancy) who've been busy mixing business and pleasure — and giving Brangelina a run for their money.