It turns out the fear and loathing you see in Tippi Hedren’s eyes as she’s attacked by vicious avians in the “The Birds” was real.

During the six months the actress spent making the 1963 movie — her big break — Hedren suffered constant sexual harassment, intimidation and cruelty at the hands of director Alfred Hitchcock, she writes in her memoir, “Tippi” (William Morrow, out Tuesday). It’s the first time she’s written about the experiences, which inspired the 2012 HBO film “The Girl.”

Working with the famed director had, at first, seemed like good fortune. Hedren, then 31, had just moved to Los Angeles from New York City, a divorced single mother with a dwindling modeling career and a 5-year-old daughter — Melanie Griffith, who would grow up to be an actress as well. Hitchcock saw Hedren in a television commercial for a meal-replacement shake and tracked her down.

Suddenly, she had a five-year movie contract — plus acting classes with Hitch and his wife, film editor Alma Reville — and a starring role in “The Birds,” the director’s anticipated follow-up to “Psycho.”

But Hitchcock’s interest in his muse rapidly devolved into obsession.

Before filming even began, the director warned Hedren’s castmates, particularly the handsome Rod Taylor, not to socialize with or “touch The Girl,” she writes. On set, every time Hitch saw Hedren laughing or talking with a man, he would turn “icy” and “petulant” and fix her with an “expressionless, unwavering stare . . . even if he was talking to a group of people on the other side of the soundstage.”

It was so bad that co-star Suzanne Pleshette pulled the ingénue aside and said, “This is so sad, because I promise, making movies isn’t always like this.”

Hitch’s antics only escalated. He told Hedren about getting an erection while directing a scene between Cary Grant and Grace Kelly in “To Catch a Thief.” Hedren writes that the director would have his driver cruise past her home, that he had her handwriting analyzed, and that he asked her to “touch him.”

Once, the portly director actually threw himself on top of her and tried to kiss her in the back of his limo.

Sexual harassment and stalking were terms that didn’t exist in the early 1960s.

“It was an awful, awful moment,” she writes. But she didn’t tell anyone because “sexual harassment and stalking were terms that didn’t exist” in the early 1960s. Besides, she adds, “Which one of us was more valuable to the studio, him or me?”

Then came the final scene, in which flocks of birds viciously attack Hedren’s character. The plan had been to use mechanical creatures, but Hitchcock, she claimed, “lied” and instead used live animals.

“Not even the greatest trainer in the world could control every move an animal makes, especially when it’s under stress,” she writes. “It was brutal and ugly and relentless.”

The torture went on for five days before a bird pecked her too close to her eye and Hedren “snapped.”

“I just sat there on the floor, unable to move, and began sobbing from sheer exhaustion,” she writes.

After that, the actress had horrible nightmares and began blacking out. When a doctor told Hitchcock that Hedren needed to take a week off, he refused until the doctor said, “Are you trying to kill her?”

Hedren’s performance in “The Birds” won raves, and, shockingly, she went on to make another film with Hitchcock, “Marnie,” just a year later. But little had changed.

On the set of that movie, Hedren says the director installed a secret door that connected his office with her dressing room and had the makeup department create a life mask of her face — not as a prop for the movie , but just for him to own.

Finally, he showed up in her dressing room and “put his hands on me. It was sexual, it was perverse,” she writes of the assault. “The harder I fought him, the more aggressive he became.”

Although Hitchcock had Hedren under contract for two more years, she did not film another movie with the director, who died in 1980.

The actress went on to make 50 films after “Marnie,” though she admits that none were as rewarding as the two she made with Hitch.

“I’ve made it my mission ever since to see to it that while Hitchcock may have ruined my career,” Hedren, now 86, writes, “I never gave him the power to ruin my life.”