The 42-year-old pop star has become the brand partner for Xeomin, an anti-wrinkle injection used to improve the look of frown lines. In an interview with People to promote their Beauty on Your Terms campaign, she explained that she uses the injectables to "feel her best" and to maintain a more natural look. "I don't want to have a frozen face. Whether it's being on-camera or performing onstage, I have to stay authentic to my emotion. When I'm on stage, authenticity in my face comes first. I have a very expressive face…”