Kate Beckinsale (in Monique Lhuillier) and Jennifer Aniston came out to celebrate celebrity yoga instructor Mandy Inger—the woman behind their enviable figures—at the launch of her book Yogalosophy: 28 Days to the Ultimate Mind-Body Makeover at the Soho House in West Hollywood. The book offers a 28-day plan to help readers achieve healthier bodies and happier minds with a mix of workouts, eating guidelines, and more. “Mandy brought yoga into my life,” Aniston endorses on the book’s cover. "This workout will change your body and your mind.” If this means we can look like Jen and Kate, we're in! Head to amazon.com to pick up a copy for $12. Plus, click the photo to see more parties.