It takes a lot to fill Betty Weider‘s shoes, and bathing suit (the ’50s pin-up had an eye-popping 18-inch waist). But Dancing with the Stars alum and bona fide triple threat Julianne Hough stepped up to the challenge. She talks about taking on the honor of playing the indomitable fitness icon and wife/business partner of bodybuilding magnate Joe Weider (played by Tyler Hoechlin) in Bigger, as well as her training regimen to replicate Betty’s impossibly hourglass figure. 

Watch Hough as the legendary Betty Weider in Bigger, in theaters this week.