Ashley Judd is spilling her guts about her less-than-idyllic childhood growing up in a famous country-music family.

Writing frankly in a shocking new memoir All That Is Bitter and Sweet (excerpted at Radaronline), the actress, 42, slams her famous country-singer mom.

"My mother, while she was transforming herself into the country legend Naomi Judd, created an origin myth for the Judds that did not match my reality," the star writes. "She and my sister [Wynonna] have been quoted as saying that our family put the 'fun' in dysfunction. I wondered: 'Who, exactly, was having all the fun? What was I missing?'"

"I loved my mother," Judd writes. "But at the same time I dreaded the mayhem and uncertainty that followed her everywhere…I often felt like an outsider observing my mom's life as she followed her own dreams."

Among her bombshells: Naomi, 65, lied to Ashley's father, convincing him that he was also dad to Wynonna, 46. (Charlie Jordan was actually Wynonna's father). Growing up, Ashley charges, "there was always marijuana in the house." Her father was "prone to taking hallucinogenics," she add.

Following her parents' divorce when she was a toddler, Ashley watched as her mom welcomed a new guy into their home, an "abusive full-blown heroin addict with a criminal record."

Even worse, she charges, "I was left alone for hours, sometimes days at a time, or when I was passed without warning to yet another relative."

The Double Jeopardy star also reveals being sexually abused by an "old man everyone knew" at a pizza parlor. "He opened his arms, I climbed [in his lap,]" she writes, "and I was shocked when he suddenly cinched his arms around me, squeezing me and smothering my mouth with his."