Emma Thompson is in negotiations to join the cast of MEN IN BLACK III, reports ComingSoon.net. She would take the role of MiB head Oh. The cast already includes Will Smith, Tommy Lee Jones, Josh Brolin and Jemaine Clement. Etan Cohen and David Koepp have penned the script from which Barry Sonnenfeld will direct. Columbia Pictures has set May 25, 2012 for the film's release.