KUALA LUMPUR, June 8 ― American actress Shannen Doherty has revealed that her breast cancer has spread to her brain.

The 52-year-old actress, known for her roles in Beverly Hills, 90210 and Charmed, shared the sad update on Instagram and wrote that a January CT scan showed "Mets” or metastasis in her brain.

Brain metastasis occurs when cancer cells migrate from the location they were initially detected to the brain.

On Monday, she posted a video on Instagram that showed her getting fitted for a radiation face mask on January 9.

On Tuesday, she shared a follow-up video of her undergoing the treatment itself on January 12.

Doherty can be seen crying in a close-up clip during treatment.

"My fear is obvious,” Doherty wrote. "I am extremely claustrophobic and there was a lot going on in my life.

"I am fortunate as I have great doctors like Dr Amin Mirahdi and the amazing techs at Cedars-Sinai. But that fear. The turmoil. The timing of it all. This is what cancer can look like.”

Her announcement received an outpouring of support from celebrities and fans.

"This is a lot to take on, still again,” said actress Selma Blair, who has faced her own health struggles with MS. "And I am wishing for all the wise peace you have learned to find you in the terror moments. To know we are holding you.”

Actress Sarah Michelle Gellar said, "You are a warrior,” while actress Mira Sorvino said, "Sending you love.”

Doherty, who was first diagnosed with breast cancer in 2015, has cited her mother Rosa Elizabeth and dog Bowie as her sources of strength in her battle with cancer.