photo: 90210 Productions

Shannen Doherty's current battle with breast cancer kept her from reuniting with her "Beverly Hills, 90210" costars at the REWind Con in Chicago this weekend (Nov. 12-13); but they made sure Brenda, Doherty's character on the show, was there in spirit.

Jennie Garth paid tribute to Doherty's courage in a touching post, writing: "To my soul sister @theshando, strongest lady I've ever known then and now," Garth addressed her Instagram post Sunday (November 13).

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"I used to be threatened by your spirit," Garth continued. "Now I'm in awe of it. You've taught me a lot about speaking my mind and not being afraid of my own power. I'm so grateful that young me got to be friends with you. But especially 'old' me! The best is yet to come on this crazy journey!! Love you!" 

She also used one of Doherty's favored hashtags, #fightlikeagirl, to cap off her moving post.

And the sweet gesture wasn't lost on Doherty. She reposted Garth's message and added a sweet note of her own.

"I'm so proud of this friendship and the mutual respect and admiration we have for each other," Doherty wrote on her Instagram page.

The love-fest comes as a sweet surprise, considering in Garth's 2014 memoir, "Deep Thoughts From a Hollywood Blonde," she confirmed fans' age-old speculations that the pair hadn't exactly gotten along during filming. Since the '90s, though, a beautiful adult friendship has bloomed out of their days of teenaged feuding.

And during the "90210" REWind panel, another of Doherty's costars voiced their deep admiration of her, too.

A photo posted by REwindCon (@rewindcon) on

"None of us are up here today without Shannen,” Luke Perry, who played Dylan on the show, said. “She’s been through a lot. She’s not doing well right now but sometimes her contributions are minimized. She’s been thrown under the bus. I’ve been accused of driving it. But she’s a very big part of the success of this show. She taught me a lot."

Here's hoping that all the love she's receiving helps keep Doherty determined to fight like a girl. She's been doing a helluva job of it already.