Holly Marie Combs Shares Emotional Tribute to Shannen Doherty: 'A Part of Me Is Missing'

"My better half of 31 years. There is a hollow in my chest and I can't seem to catch my breath," the actress wrote of her former 'Charmed' costar, whom she remembered as a "fierce fighter til the end."

Holly Marie Combs is honoring her best friend, Shannen Doherty , following her recent passing.

On Monday, the actress posted an emotional tribute on Instagram, in which she mourned the death of her former Charmed costar, who died at the age of 53 on Saturday after a years-long battle with cancer.

Combs shared a series of photos of herself and Doherty throughout their nearly three decades of friendship.

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"My better half of 31 years. There is a hollow in my chest and I can't seem to catch my breath," she began in her heartbreaking tribute. "A part of me is missing even though I know exactly what you would say to me right now. I know exactly what you would tell me to do right now."

"I know your undying spirit will live in me and my kids who you loved as your own," continued Combs, who shares sons Riley, 20, and Finley, 17, with ex-husband David W. Donoho. "They will walk with your sense of purpose and pride. They will be truthful and stand up for what is right. No matter what and zero f--ks given. Your fire will live on in them and the many other Charmed ones you helped raise."

Combs ended her touching message by remembering her friend as a "fierce fighter til the end."

"My most ardent champion. My loyal protector. My best friend. You taught me the meaning of family. You were and will be forevermore my sister," she concluded. "I love you."

On Sunday, Doherty's rep, Leslie Sloane, announced the news of her death.

"It is with a heavy heart that I confirm the passing of actress Shannen Doherty. On Saturday, July 13, she lost her battle with cancer after many years of fighting the disease," Sloane said, per TMZ . "The devoted daughter, sister, aunt and friend was surrounded by her loved ones as well as her dog, Bowie. The family asks for their privacy at this time so they can grieve in peace."

Doherty was first diagnosed with breast cancer in 2015. While she was believed to be in remission in 2017, in 2019 she learned her cancer had metastasized as Stage 4 in her brain and bones.

Late last month, Doherty shared on her podcast Let's Be Clear that she started a new round of chemotherapy . Despite being told that her Stage 4 cancer was incurable, she shared that she felt "hopeful" and was maintaining a positive outlook.

Following the news of her passing, celebrities, including several of Doherty's former costars, took to social media to pay tribute.

In addition to Combs, other Charmed alums mourned Doherty's passing on social media.

Alyssa Milano released a statement that read: "It's no secret that Shannen and I had a complicated relationship, but at its core was someone I deeply respected and was in awe of. She was a talented actress, beloved by many and the world is less without her. My condolences to all who loved her."

Rose McGowan , who also starred on Charmed , posted a moving tribute on Instagram, sharing a complication video that featured photos of Doherty.

"Shannen Doherty had the heart of a lion. Passion for craft is often mislabeled as trouble. Shannen was passion. I met her in the 90s and was awed. Getting to really know her later in life, a beautiful gift. This woman fought to live. Shannen knew how to be a star because she was one since childhood," McGowan wrote. "Her work ethic inspiring to the end. Shannen’s great love for directing, for acting, Holly, her friends, her parents, dog and her beloved fans was legendary."

"Our lives had been intertwined in a unique way," McGowan added. "We laughed at dark forces who wanted us to hate each other, instead we chose love and respect. A soft-hearted badass as there ever was. A force of energy that will live forever in hearts. May angels and God carry her to the holy kingdom where she is healthy, young and wild forever. Rest now warrior, we will never forget you dear sister 🎭."

"You showed me what strength is," Brian Krause wrote. "You taught me to be fearless and live with purpose. To know your value and stick to your determinations. Forever loved! Truly heartbroken 😔

On Monday, Krause gave an emotional introduction to the re-launched House of Halliwell: A Charmed Rewatch Podcast -- which Doherty had just joined last week -- while reflecting on the shocking news of her death.

"I come to you this evening with a heavy heart after learning the news of Shannen Doherty's passing just yesterday afternoon," Krause said as he began the episode.

He continued, "I know all of us here at the House of Halliwell, iHeart media, social media, all over the world are shocked, devastated. Too young, too talented, too loving, too grateful, too early. Shannen will dearly be missed and we are so honored that she had come on with us, or, had us along with her on this new incantation of the House of Halliwell."

Krause, meanwhile, who played Leo Wyatt, Combs' husband, on the WB series, revealed since announcing the relaunch and the news that Doherty would be joining the podcast, the Beverly Hills, 90210 alum had recorded four episodes of the rewatch podcast, all of which they still plan to release.

"We were lucky enough to record four episodes in the last week or so, and Shannen was just so motivated and determined to help make this show a success and give all of you more insight into what it was in the making and the fun and the behind-the-scenes of Charmed ," Krause said.

Touching on her work ethic, the 55-year-old actor added that if Doherty "wanted something done, she got it done, and that's something I learned a long time ago, watching her on set and work and be such a professional and so good at what she did."

Shannen Doherty’s Charmed Costar Shares Details on Her 'Work Ethic' In Last Days