Does that name not sound familiar? Close your eyes and say "Marcia, Marcia, Marcia!" in your head, and that voice you'll hear is probably hers.
Cox starred as Jan Brady in 1995's "The Brady Bunch Movie" -- the over-the-top comedy film based on the iconic '70s television series "The Brady Bunch" -- which put the classic characters in a modern day setting and spawned both a movie and TV sequel.
Jennifer turns 42 today, and a lot has changed for her and the other Brady kids over the past 17 years!
Click "Launch Gallery" above to see how the cast has aged, plus find out what they're doing now!