Shannen Doherty couldn’t be more grateful for having her mom by her side as she fights breast cancer.

The 45-year-old actress, best known for her role as Brenda Walsh in “Beverly Hills, 90210,” took to Instagram on Saturday to thank her mom Rosa for her never-ending support.

"Sometimes there's nothing like a mother’s love to help get you thru,” Doherty wrote, along with a touching photo of herself cuddled up in her mom's lap. “Thank you mom for always being there and being so strong for me. |I love you.  #mamarosa, #cancersucks and #fightlikeagirl.”

The “Charmed” alum has been very open about her battle with breast cancer. Just three days ago, Doherty opened up about what it was like for her to undergo chemotherapy for a day.

“Chemo day. A day many of us dread,” she captioned a photo of her in bed.  “Strength gets us thru but every once in awhile, you just want to hide in bed and let chemo day pass you by. #currentmood #currentsituation #chemoday #fightlikeagirl.”

Doherty revealed that she has breast cancer in a lawsuit she filed in August against her former business managers. In the suit, Doherty claims that her former management team failed to pay her medical insurance premiums which led to her being uninsured for several months. Because she was not insured, she claims that she was unable to regularly see a doctor, and as a result, her breast cancer metastasized.

Earlier this month, Doherty confirmed to Entertainment Tonight that her cancer had spread. "I had breast cancer that spread to the lymph nodes, and from one of my surgeries we discovered that some of the cancer cells might have actually gone out of the lymph nodes," she revealed . "So for that reason, we are doing chemo, and then after chemo, I'll do radiation."

"The unknown is always the scariest part," she added. "Is the chemo going to work? Is the radiation going to work? You know, am I going to have to go through this again, or am I going to get secondary cancer?"

"Everything else is manageable," Doherty explained. "Pain is manageable. You know, living without a breast is manageable. It's the worry of your future and how your future is going to affect the people you love."

Shannen Dohery Shannen Doherty took to Instagram on Saturday, Aug. 13, to thank her mom Rosa for her never-ending support as the “Beverly Hills, 90210” alum battles breast cancer. Pictured: Doherty attends 18th Annual Webby Awards on May 19, 2014 in New York. Photo: Getty Images/Brad Barket