Sarah Michelle Gellar took to Instagram today to pay tribute to her close friend, Shannen Doherty, who passed away on Saturday at 53. Known for her roles in Beverly Hills, 90210 and Charmed, Doherty was diagnosed with Stage 4 breast cancer in 2015. “How do you possibly find the right words to sum up 30 years of friendship?” Gellar, 47, posted on Instagram. “I keep reminding myself it only hurts this much because, there was so much love. Thank you, for all your kind words and support. I love all the messages about how @theshando was important to you. So let’s honor her.” The Buffy the Vampire Slayer star continued: “More than anything, Shan loves animals, especially dogs. In her memory let’s support our favorite animal charities. Whether that’s donating money, stopping by your local shelter and just offering cuddles and walks to animals housed there or even just tagging them in the comments so other people can learn about their work.” Gellar said she knew such gestures “would make our girl happy (and illicit that deep throaty laugh we all loved) 💔 💔💔.” Gellar shared numerous photos of their time together, both on her main feed and Instagram Stories.