Christina Applegate was abused when she was just five years old

Writing in her new memoir You With the Sad Eyes in an extract obtained by People magazine, Christina revealed: "I knew every part of it was wrong. I felt sick and scared and sad...

"I never fully felt comfortable being touched, and that's true still. I've never felt comfortable with it my whole life, really, and all because of that girl forcing me to do something I barely understood but that I knew was shameful."

The Dead to Me star's home life was unstable in her early years thanks to her mom's struggle with heroin addiction and a physically abusive boyfriend, who also lashed out at Christina.

She wrote: "I think I had kind of the worst situation from 3 to 7. But there was stuff like that going on in all our homes. Single moms, men coming in and out, drugs."

Christina insisted she doesn't want people to read her book to see her as a victim, but hopes her story can resonate with readers.

She told People: "Because a lot of it is so heavy. I had someone say to me, 'Are you doing this because you're being a victim?' I'm like, 'No, I'm empowering other people out there.' At least I hope to.

"I hope that some girl or boy or anyone who's gone through being molested or beaten or anything I've gone through can go, 'Oh my God, okay. I'm going to be okay.' "

The former Married... With Children actress has 15-year-old Sadie with husband Martyn LeNoble and when it comes to parenting, she doesn't "buy into this thing of you shouldn't be your kid's friend."

She added: "Because I am, especially now. I'm her biggest supporter. I fight for her at every turn. And I drive her to school blaring Sex and Candy by Marcy Playground. That's kind of me in a nutshell."

Christina isn't afraid to laugh at herself amid her battle with multiple sclerosis (MS).

She said: "Like I put my diaper on and go into her room.

"I toddle in with a tank top above my belly, and sometimes I draw faces on my belly button. She's like, 'Mom. Mom! Just stop.' "