"This is a true #tbt," Doherty captioned the epic snap. "#beverlyhills90210 is to this day the biggest tv show of its kind I worked on. A true iconic show that reached and touched not only young people, but bridged the gap to their parents."
"I'm very proud of this show. @jason_priestley #brendawalsh #twins," she conluded.
Doherty later added another shot, paying tribute to her on-screen boyfriend, Luke Perry, who played Dylan McKay on the series.
"#tbt they were so happy here!!! Anyone remember this episode? #brendaanddylan #90210," she captioned the pic.
These days, many of Doherty's Instagram posts revolve around her battle with breast cancer, but her former 90210 costars will always have her back.
In fact, Perry and Jennie Garth gave a special shout-out to Doherty during a reunion at REWindCon in November.
"None of us are up here today without Shannen," said Perry. "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," he continued. "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. I’m glad she was my scene partner. She was great at what she did in the character with me."