Kim's just weeks away from the big day -- her wedding to Kris Humphries will be August 20 in Montecito, Calif. -- so, as any Hollywood starlet worth her weight in Harry Winston diamonds knows, a girl's gotta get her booty to boot camp and shape up for her big Vera Wang moment!

Kim's determined to fit in her custom-made gown ... and not only fit into it -- WOW in it! And we're behind Kim all the way!