He was joined by longtime wife Rachel Campos-Duffy, who fans will remember from "The Real World: San Francisco":
David "Puck" Rainey, also of "The Real World: San Francisco" fame, made an appearance to support the fight:
Norman Korpi, from the very first season of "The Real World," also came out to listen to the day's discussion:
The former competitors and housemates joined Laurel Stucky -- star of "The Challenge: Free Agents" -- to show their continued support of cancer patients and survivors:
Rachel posted a special photo of the group on Twitter with the caption, "Bringing the @mtv real world crew for a great cause. @normankorpi @laurelstucky @mtvpuck #30daysofteal #COCCnow":
In addition, Brown's sister Megan spoke at the event about the importance of bringing awareness to the disease:
Duffy himself reiterated Megan's message at the caucus, which was recorded as part of an upcoming MTV short-form documentary about ovarian cancer. "We need to re-energize our focus and our efforts as a society to beat this cancer. #coccnow #diemstrong," he wrote on Twitter.
If you'd like to write about your memories of Diem Brown, please do so in the comments section. And for a look back at her inspiring life, watch MTV's very special tribute to her: