As Shannen Doherty wages war on the breast cancer that recently spread to her lymph nodes, she has one co-pilot by her side: Her mom, Rosa.

On Saturday, Aug. 13, the "90210" alum, who shaved her head a few weeks ago, shared a moving photo of the two of them sharing a tender moment.

"Sometimes there's nothing like a mothers love to help get you thru. Thank you mom for always being there and being so strong for me. I love you. #mamarosa#cancersucks #fightlikeagirl," she captioned the black and white image.

The 45-year-old actress was diagnosed with cancer in 2015. She appeared on Entertainment Tonight earlier this month with an update on her condition and treatment.

"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. So for that reason, we are doing chemo, and then after chemo, I'll do radiation," she said.

"The unknown is always the scariest part. 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. 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 that you love."

According to Us Weekly, she plans to undergo eight rounds of chemotherapy. So far, they've been extremely hard for Shannen.

"Chemo day. A day many of us dread. 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," she wrote on Instagram recently.

In another post, she explained, "Each person's cancer journey is different. For me, chemo has been terrible and believe me, we have tried almost everything. So days like this have become a bit of the norm. I'm learning that it's ok to fall into bed and give in to the exhaustion or nausea or aches. I've learned a lot of that thru all the beautiful people who have shared their personal stories with me right here on Instagram. Thank you. Btw, it doesn't hurt to have [my dog] comfort me So back to my nap. Thank you for your prayers, well wishes and stories. They help so much."