In an explosive new memoir, Anjelica Huston reveals brutish beau Ryan O’Neal head-butted her in a violent rage – and she was busted for drugs with notorious director Roman Polanski!

The National ENQUIRER obtained a copy of the tell-all, titled “Watch Me,” and this exclusive sneak peek offers an electrifying look at the star’s darkest Hollywood moments.

Anjelica, 63, writes that she was living with O’Neal in the late 1970s when he suddenly attacked her during a party at a mansion in Beverly Hills.

She was walking from the bathroom to the mansion’s dining area when she stopped for several minutes rather than cross the path of a performing belly dancer.

For some reason, this agitated O’Neal and he bolted outside. “He turned on me, grabbed me by the hair and hit me in the forehead with the top of his skull,” the actress writes.

“I saw stars and reeled back. Half blind I ran away from him.”

She retreated to a bathroom where she was comforted by security guards, along with O’Neal’s brother Kevin, who witnessed the attack.

The Oscar-winning star – whose father, legendary director John Huston, and grandfather Walter Huston also won Oscars –finally agreed to let O’Neal into the bathroom to speak to her alone. But she writes: “Ryan was batting me about the head with an open hand. Then abruptly he left.”

Anjelica dumped O’Neal shortly after returning to their home to find him sitting in the bedroom with an ice pack, “chuckling” and saying, “I’ve got quite a headache.”

After that, she reunited with longtime love, actor Jack Nicholson, whom she’d dumped for O’Neal.

Anjelica writes that she fell head over heels for Jack the minute she saw him in the 1969 classic “Easy Rider.” “It was Jack’s combination of ease and exuberance that had captured me from the moment he came on screen,” she gushes.

“I think it was probably upon seeing the film that, like many others, I first fell in love with Jack.”But she says watching female fans fawning over Jack, and his basking in their attention, strained the relationship.

When she confronted him about sleeping with an ex, she writes that he blew her off, saying, “‘Oh Toots, it was just a mercy f…’” “That was the first time I’d heard copulation described as an act of compassion – not that he’d ever vowed to be faithful to me but somehow he thought it was an acceptable answer,” she writes. Anjelica eventually walked out on Nicholson for bad boy actor O’Neal, but writes: “I regretted leaving Jack. I hated causing him pain.”She chose not to live in Jack’s mansion, but in a nearby home that he bought for her.

It was at Jack’s house where she encountered his friend, “Chinatown” director Roman Polanski, with a girl who was very tall and very young. Anjelica later learned that the girl was just 13.

“He introduced me to her and said they had been taking pictures … I thought no more of it,” she wrote.The next day Polanski was back at the house with a team of L.A. detectives, including an aggressive young cop who barked, “You better show me the drugs otherwise we taking this place apart.”. She writes: “They started to go through my handbag where they found a gram of cocaine. Roman and I were bundled into the back of two separate police cars. We were under arrest.”

Anjelica says that she felt humiliated for shaming her family name, and when she crossed paths with Polanski during the booking process, he told her: “I’m sorry for this Anjelica.”