To honor the 20th anniversary of the show, star Sarah Michelle Gellar tweeted her appreciation of "the greatest fans ever."

In a longer letter on Instagram, Gellar also thanked the cast and crew, and reflected on Buffy's place in pop culture history.

"That first season, we liked to think of ourselves as the little show that could. While we knew the potential, I don't think any of us saw the lasting impact our show would have," she wrote.

"As an actor, you wish for that one role where you can leave your mark and forever be remembered, with Buffy I got so much more. She's a feminist challenge to gender hierarchy."

20 years ago today, I had the greatest privilege to bring Buffy to your tv screens for the first time. It was a long and challenging road to get there. First the movie, then a passed over pilot presentation, and eventually a mid season time slot on a little known network. That first season, we liked to think of ourselves as the little show that could. While we knew the potential, I don't think any of us saw the lasting impact our show would have. As an actor, you wish for that one role where you can leave your mark and forever be remembered, with Buffy I got so much more. She's a feminist challenge to gender hierarchy. Buffy may have been the Chosen One, but I was the lucky one. Thank you to Gail Berman for always believing there was a show in that movie. Thank you to Joss Whedon, for trusting me to give life to one of the greatest female characters ever created. Thank you to David, for always being my Angel. Thank you to James for understanding that while Buffy and Spike may have been love/hate, I have nothing but love for you. Alyson, as any woman knows, you are nothing without the love and support of great female friends, so thank you for being that. Michelle, you will always hold a key to my heart. Thank you to all the incredible actors for seven seasons of amazing performances. I would be remiss if I didn't mention the incredible crew that worked tirelessly (and also really tired) to bring this show to life. And lastly, but most importantly thank you to all of you, the fans. We made this show for you, and your unwavering support has kept this show going long past our seven years. You are everything. And always remember..."if the apocalypse comes, beep me" #buffyslays20

A post shared by Sarah Michelle (@sarahmgellar) on

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