Ann B Davis was the only then-living main cast member of the Brady Bunch to not appear on the show.
Due to Robert Reed having died in 1992 and Ann B Davis not appearing on the show for reasons not disclosed, Robbie Rist, who played Cousin Oliver in the final 6 episodes of The Brady Bunch, appeared with the rest of the cast to be the eighth contestant, thus making this the only time he ever appeared with the original cast for any TV reunion. (He was the first contestant eliminated.)