"She's just one I could've spent more time with," shared Knight, on the verge of tears.
Henderson died from heart failure on Thursday, surrounded by her four children, her rep told ET. It's safe to say that over the years, Henderson remained America's favorite TV mom, but for Knight, she meant so much more.
"There was one show where we were in the backyard with our mitts and throwing the ball around, and she was dressed like she was ready to play with us, and I think it was at that point I thought she was really cool," Knight recalled. "She could be one of the guys and very much like mom, like a mom you'd want to have, and America has responded to [her] in the same way."
"She was just a wonderful kind of warm and stern mothering figure. She, to me, was just someone I never wanted to disappoint," he continued. "I admired her so much and respected her as a child… and I've lived like that ever since."
"It's a terrible tragedy that we've lost her, but we all own her," Knight emphasized. "I know that I will live being who I am with her, because she's had a very important role in my life. I'm a good deal of who I am because of her."
Barry Williams, who played Greg Brady on The Brady Bunch, expressed similar sentiments during an interview with KOLR/KOZL, a CBS affiliate, on Friday.
"I was just waking up when I got the news. It stunned me. It still has. Florence's passing is very unexpected," he shared, adding that she looked "vibrant and alive" during her appearance on Dancing With the Stars on Monday.
"There was never a question that we would be lifelong friends. From the time that I met her I had a great affinity for her and then an attraction to her. She's played so many different roles in my life as a mother, as a professional, as a mentor and she was inspiring to me as well," he explained, before reflecting on his teenage crush on Henderson, 20 years his senior.
"I think she knew that I had a crush on her and I think that was kind of amusing. We went out to dinner one night to talk about music and that side of show business, performing in Vegas and showrooms and also on Broadway, and I was very interested in that. I used that as an excuse to pick her up in the car and take her out and try an steal a kiss. Which I did!" he recalled, sharing that the two never actually dated.
While it's been decades since The Brady Bunch last aired, Williams said the cast has remained close, and are "leaning on each other" for comfort after Henderson's death.
"It very challenging again because it's so fresh and so unexpected. But that's what we do and that's who we are," he said. "We have now shared almost all the major milestones of our lives together. This is a particularly poignant one."
"She managed a great deal in her life. She was maternal and she had two families. She had we six Brady's but she has 4 kids of her own and that's an awful lot to take care of and keep balanced," he continued. "Somehow she managed to do that and do it well. To the point that all of the Brady kids are friends with her own children."
"I think it's important to know that many people share this loss. She will be remembered. She will be loved for a long time," he added.
Henderson's TV daughter, Eve Plumb, who played Jan Brady on the series, also offered a statement to ET.
"Florence was a wonderful role model for me and all of us 'kids.' She taught me how to be a professional actor by her example of preparedness and respect for the work and her fellow cast and crew members," she said. "She was what I came to call a 'good celebrity' in that she would always pose for a picture, sign an autograph, and was very attentive to her fans."
"She was also loving, warm, generous, and could tell a funny, dirty joke. I'm fortunate to have been able to know and to work with her. She will be missed by her children, grandchildren, and us 'kids,'" Plumb concluded.
ET last spoke with Henderson in June, where she talked about the possibility of a Brady Bunch reboot.