Doherty revealed her breast cancer diagnosis in August 2015

Shannen Doherty has openly documented her battle with cancer — and her close friend Sarah Michelle Gellar couldn’t be prouder of her.

“Shannen’s incredible,” Gellar, 39, told Entertainment Tonight on Monday. “What she’s done for other women going through it is so brave, and that’s what real bravery is — to be able to go through the hardest time of your life and show people it’s okay to be scared, and it’s okay to be vulnerable, and you can do it.”

Doherty, 45, exclusively revealed her breast cancer diagnosis to PEOPLE in August 2015. Since opening up about her diagnosis, the actress has frequently shared health updates with followers and fans on social media, including her first day of radiation and heading into appointments with her mother by her side.

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In February, Doherty and Gellar attended an intense dance workout class together, which they documented heavily on social media.

“The fact that she gets up and goes to those dance classes? The last thing I want to do is go to these really hard dance classes and sweat that hard and work that hard,” Gellar admitted. “But I have to remind myself that if she’s getting up there and doing it, then it’s important that I do it, too.”