FANS of hit '70s sitcom The Brady Bunch have been shocked by claims clean-cut TV sisters Marcia and Jan were real-life lovers.
Actress Maureen McCormick, who played Marcia, has reportedly revealed the lesbian love affair in a tell-all autobiography.
US press reports say the book details how McCormick enjoyed much more than a sisterly relationship with Eve Plumb, who played her less glamorous sister Jan.
The book, Here's The Story, will be released next year through Harper Entertainment, a division of HarperCollins Publishers.
"The most explosive comments will be how the then blonde, blue-eyed cutie developed a crush on Eve Plumb, which led to some sexual play," a source told America's National Enquirer magazine.
"This book will certainly come as a shocker. While Maureen is not a lesbian, she reveals there were some sexual high jinks going on behind the scenes."
Described as a "cautionary tale", the autobiography will document McCormick's life as a child actor, as well as cover her struggle with an eating disorder, her drug addictions and battle with depression.
"I've learned that overcoming my demons and weathering the tumultuous storms of my life is a process," McCormick said.
"I have arrived, for the moment at least, in a solid and secure place, which is allowing me to visit my past without fear.
"Writing this book has been such a cathartic experience. I hope it will not only shed light on who I am and how I got here but, more importantly, remind the readers that there truly is a light at the end of any tunnel."
The Brady Bunch – about a blended family of three boys and three girls – remains one of the most repeated TV shows in syndication.
It has also proved to be a fountain of gossip about the private lives of the actors.
Florence Henderson, who played mum Carol Brady, went on a date with Barry Williams, who played her on-screen son Greg, during the show.
Williams also dated McCormick for two years during the show, which originally screened from 1969-74.