"Smoking is linked to various types of cancer, including breast cancer," Aliabadi noted. Other lifestyle habits to consider that may lower the risk of developing breast cancer, according to the doctor, include:

Staying physically active, maintaining a healthy weight (being overweight or obese increases the risk of breast cancer, especially after menopause); limiting alcohol consumption (no more than one drink a day, or eliminating altogether); eating a healthy diet rich in fruits, vegetables, whole grains, and lean proteins and limiting intake of processed and red meats.

Knowing your family history is also important, Aliabadi advises, as is following the recommended guidelines for breast cancer screening because early detection can improve outcomes and survival rates.

And, if it's an option, breastfeeding has been associated with a reduced risk of breast cancer, the doctor noted.

In any case, when public figures like Munn share their stories, it gets people thinking. Read on for a sampling of the outpouring of support she received from the likes of Jessica Chastain, Minka Kelly, Julianne Hough and many more: