Prince Harry caused a sensation last week when he revealed that the pressures of royal life had driven him to drink and do drugs.

“I was willing to drink, I was willing to take drugs, I was willing to try and do the things that made me feel less like I was feeling,” Harry told Oprah Winfrey, who is partnering with him on a documentary series on mental health. He added, “I was just all over the place mentally.”

That sounds a lot like another senior royal who, like Prince Harry, lost a parent early in life, had almost zero chance of claiming the throne, and pursued a love interest who wasn’t apropos of royal tradition.

She lost her father, King George VI, when she was 22. Her sister Elizabeth became queen. And Margaret fell in love with British Air Force officer Peter Townsend, a divorcée she ultimately broke up with to maintain her royal privileges. (She wound up marrying — and divorcing — someone even less suitable: photographer Antony Armstrong-Jones.)

Princess Margaret, as the Netflix series “The Crown” frequently shows, drank excessively. Though her father died of lung disease from smoking, she generally smoked more than 60 cigarettes a day. She was frequently depressed.

Harry and his wife, Meghan, Duchess of Sussex, a biracial American actress, described feeling depression and anxiety before they walked away from royal life. They now live in Southern California.

Harry traces his struggles back to the death of his mother, Princess Diana, in a high-speed car crash in a Paris tunnel in 1997. He compared being a royal to being an animal on display at a zoo.

“I thought my family would help, but every single ask, request, warning, whatever it is, just got met with total silence, total neglect,” Harry told Oprah in the documentary series he co-created with her, “The Me You Can’t See,” for Apple TV Plus. “We spent four years trying to make it work. We did everything that we possibly could to stay there and carry on doing the role and doing the job.”

Prince Harry opens up about excessive drinking and drug use in a documentary series he co-created with Oprah Winfrey that comes out May 21 on Apple TV Plus. (Reuters)

Princess Margaret apparently felt the same way about her sister’s lack of response to her own struggles.

In December of 1966, Margaret was “smoking and drinking excessively,” according to Andrew Morton’s dual biography of the sisters. “The princess, melancholic and despairing, took to calling friends in the dead of night to vent her grievances.” Her friends were so concerned about her mental health that they reportedly bugged her house.

The next month, Margaret was hosting a party and called a friend late in the evening threatening to throw herself out her bedroom window if he didn’t come over. The friend called the queen, Morton wrote, and she reportedly replied, “Carry on with your house party. Her bedroom is on the ground floor.”

Morton, a longtime royal observer and biographer, assessed the queen’s reaction bluntly.

“The queen’s response matched that of the queen mother and other members of the royal family,” he wrote. “They lived in a world where illness was dealt with by going for a long walk, and mental illness was ignored altogether. Like the Queen’s approach to central heating — ‘if you are cold put on a sweater’ — her response to sickness, especially her sister’s, was brisk and no-nonsense.”

Perhaps the most serious incident stemming from Margaret’s mental health struggles occurred in 1974, when she took a handful of sedatives in what some royal observers thought was a suicide attempt — a theory Margaret denied, though in a haunting way.

“I was so exhausted because of everything, that all I wanted to do was sleep,” she told her official biographer, Christopher Warwick. “And I did, right through to the following afternoon.”

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