The actress and new Braun ambassador firmly believes the most attractive women are happy and healthy and claims true beauty comes from being in a positive place.
Asked for her top tip to help insecure women, she told Aufeminin.com: "Don't focus on negative things, concentrate on the good times you have with your loved one. If you want to change your appearance because you don't feel good about yourself, go for it and work hard to reach your goals.
"But at the end of the day, focus on your good qualities because true beauty comes from confidence in yourself, happiness and kindness. Regardless of your appearance, that's what I think of as a beautiful women."
Jessica - who has daughters Honor, five, and Haven, two, with her husband Cash Warren - is regularly hailed as one of the sexiest women in Hollywood, but insists her perfect image has taken years of hard work to achieve.
The 'Sin City' star added: "I don't have a perfect body. I know how to emphasise my curves, that's all. I choose clothes that accentuate my body, but it's taken years of practice.
"I do sport even though it's not enough in my opinion. I practice yoga, dance, I drink lots of water and I eat healthily. At least, I try."