Scotty Bowers was a 23-year-old petrol station attendant on Hollywood Boulevard when the actor Walter Pidgeon pulled up to the pump and asked the dimpled blond to jump in his Lincoln. It would be the ride of his life. Pidgeon was gay, claims Bowers in his autobiography Full Service: My Adventures in Hollywood and the Secret Sex Lives of the Stars, and that afternoon they became lovers. Bowers himself transcended labels. Years later, he startled sexologist Dr Alfred Kinsey by checking off every sex act on his list (and took him to orgies to prove it). Guys, girls, spouses, kings, consorts – and a three-way with Ava Gardner and Lana Turner. Bowers had done it all.

“[Kinsey] came looking for me,” says Bowers, now 95, on a hot afternoon in a Hollywood courtyard apartment. “Things he thought impossible, I came up with.” With his devilish blue eyes and thick white hair, it is easy to picture why he was popular. He burns with energy, as though he spent his retirement stoking gossip he vowed he wouldn’t spill while his lovers were alive. J Edgar Hoover? “A drag.” Vivien Leigh? “A hot, hot lady.” Wallis Simpson? “A real ballsy chick.”

Bowers (second from left, back row) with friends. Photograph: Courtesy of Greenwich Entertainment

Bowers used to turn tricks in this same building. Today, the vintage-style pad belongs to the director Matt Tyrnauer, a former Vanity Fair journalist who recently reworked Bowers’ memoir into the eyebrow-raising documentary Scotty and the Secret History of Hollywood. Tyrnauer, sitting next to Bowers and gently nudging his digressions on track, confirms that he called the Kinsey Institute to check Bowers’ tale. They knew exactly who he was.

Everyone knew Bowers. George Cukor, Gore Vidal, Merv Griffin; Tyrone Power referred to him in letters, interviews and biographies, calling him “Scotty”, “Sonny”, or just “the gas station on Hollywood Boulevard”. Tennessee Williams hand-wrote a 40-page story about him, which Bowers found embarrassingly over the top.

“I said: ‘Tennessee, forget that bullshit,’” says Bowers. “I should have kept it.’” Instead, for decades, people pushed him to write down his own memories. “I kept putting it off and putting it off, and all of a sudden, almost everyone they wanted me to write about was dead.”

Lana Turner and Ava Gardner, with whom Bowers claims to have had a threesome. Photograph: Keystone/Getty Images

In 1946, the year he met Pidgeon, Bowers was competing with millions of other returning second world war veterans for work. Canoodling with a celebrity for $20 made more sense than digging a ditch for $10. After Pidgeon spread the word about his new friend, more luxury cars began to cruise by. Soon, Bowers’ side-hustle had expanded to a parked trailer with two king beds, glory holes in the bathroom and a battalion of good-looking men and women to fix up with some of the biggest names in Hollywood. Bowers boasts that he paired Cary Grant with Rock Hudson back when the Pillow Talk star was still named Roy, and introduced Katharine Hepburn to 150 lovely brunettes. As for Hepburn’s rumored paramour Spencer Tracy, Bowers says he slept with him, too.

Hepburn and Tracy’s complex relationship is a fascinating example of Hollywood’s hypocritical – and literal – moral code. Publicists decided it was better to pretend the friends were having an affair than explain the real reason why Tracy wasn’t living with his wife Louise, to whom he stayed married until his death. A heterosexual affair was forgivable – even romantic – and it wouldn’t get either actor fired. After Fatty Arbuckle was put on trial for the rape and murder of Virginia Rappe, the studios began to add a clause in their contracts forbidding actors from committing any offence that risked public hatred, contempt or ridicule. While the courts found Arbuckle innocent –twice – the Hollywood moguls believed just a whiff of indecency could destroy the entire industry. The swinging days of the early silent era ended overnight. Performers became studio property: they were told how to dress, how to behave, and who to date, or at least pretend to.

Bowers in uniform in the 1940s. Photograph: Greenwich Entertainment

It was a lucrative lie. Roy Harold Scherer got his teeth capped and became Rock Hudson. When the tabloids began to nag Hudson to get married, the executives betrothed him to his lesbian secretary Phyllis. Archibald Leach was rechristened Cary Grant and wed to the great beauty Barbara Hutton, although the love of his life was screen cowboy Randolph Scott, with whom he lived for 12 years as a “roommate”. Bowers says in his book: “The three of us got into a lot of sexual mischief together.”

Living double lives took a toll. Eventually, Hudson began drinking a bottle of scotch a day and recklessly sleeping with strangers. Grant tried psychedelic therapy and spoke in quips that hinted at his unfulfillment. “I played at being someone I wanted to be until I became that person, or he became me,” he told his biographer. Even his most famous quote – “Everyone wants to be Cary Grant. Even I want to be Cary Grant” – sounds like a whispered confession, or maybe a misdirection. What if he just wanted to be as free as Archibald Leach?

Bowers bedded so many movie stars that he didn’t have time to see their movies. “A movie takes a couple hours. I was busy every minute.” When his daughter, Donna, died, he went back to work that day. He shared a home with her mother, his longtime partner Betty, but slept there only a few times a year. In the documentary, he teeters towards admitting regret for spending most nights in someone else’s bed. But he candidly admits his only true passion was money. He grew up hungry during the Depression era, and, as a young teenager, he turned tricks for two dozen Chicago priests who paid him in quarters. That would be abuse in everyone’s eyes but his. In the documentary, Tyrnauer repeatedly presses Bowers about his childhood, and does so again today.

“You’re very intent on the fact that you don’t perceive yourself as a victim,” says Tyrnauer.

“I did what I wanted to do,” maintains Bowers.

“That is not the conventional perspective at all, but it is his perspective and I don’t judge him for that,” says Tyrnauer. “I think people get to define who they are and tell their story and express their beliefs.”

Executives married off Rock Hudson to his lesbian secretary, Phyllis Gates. Photograph: Kobal/Rex/Shutterstock

“I do think that different people are different, that’s very true,” replies Bowers. “I’m speaking for myself only.”

As an adult at the petrol station, Bowers never took a cut of other people’s cash. To him, that meant he wasn’t a pimp; he was a purveyor of joy. “The most important thing was company,” says Bowers. The LGBTQ community didn’t have many safe places to connect at that time. Homosexuality was illegal in California until the 1970s. When the Los Angeles Police Department vice squad – “the sexual Gestapo,” says Tyrnauer – barged into a gay bar, patrons risked being arrested, shaken down for cash, shipped to a mental institution, and possibly lobotomised. The LAPD targeted the Hollywood glitterati because they had careers to protect and money to spare.

When the petrol station became too famous, Bowers became a for-rent party bartender, which gave celebrities an even better excuse to invite him into their homes. Even that was risky. One cop memorised Bowers’ car registration plate and would pull him over, scare him a bit, and then undo Bowers’ pants while complaining about his miserable marriage. “I hope he found happiness,” writes Bowers, charitably.

The vice squad is responsible for Bowers’ impressive memory. Midway through one aside, he recites the address of a silent movie star who has been dead for 45 years. Terrified of a raid, he rarely wrote down his friends’ information. “It was all in my head,” says Bowers. “I never kept anything. If I wrote down a number, I had it in my hand until I tore it up.” Even then, he would swap the first and last digits to ensure the person’s identity couldn’t be cracked, a trick inspired by the Navajo code talkers.

Now, Bowers has no secrets. Critics have slammed the book and the documentary for outing celebrities without consent. In the film, Tyrnauer includes a film fan arguing that legendary stars deserve more respect. Bowers counters: “What’s wrong with being gay?” Others have thanked him for sticking up for the real person underneath the studio gloss – for revealing their truth the way they might have if they were alive today. It is impossible to know how Hudson and Grant would have chosen to live in a country that legalised gay marriage. Perhaps their lives would have been happier. Although, Bowers notes, even in 2018: “Everything’s not going to be out in the open.” More actors are out, but now must prove they can play both gay and straight characters. Neil Patrick Harris has succeeded; Matt Bomer is trying. Some have decided that it is still easier to hide.

Asked if he is biting his tongue about anyone alive, Bowers blurts out the name of a beloved actor and her “169% gay” husband. He is dead; she isn’t. So, Bowers will wait. “Let me tell you something: when you’re dead you’re dead,” he insists. Later, when the conversation turns to Kevin Spacey – Bowers claims to know one of his exes – Tyrnauer steadily repeats that Bowers’ information about the alleged perpetrator is merely secondhand. The director is clearly, and correctly, aware of the complexities of talking sensitively about sex in the era of #MeToo. But after eight decades of secrecy Bowers sighs: “Poor Kevin Spacey, he was right in the middle of a picture and they dumped him and everything.” Thanks to #MeToo, morality clauses are making a comeback. This time, one hopes they will only be wielded for good.

Cary Grant (right) with his ‘room mate’ Randolph Scott. Photograph: Snap/Rex Features

Hollywood journalist Liz Smith once quipped: “All this crap about ‘coming out’! Honey, I don’t think I have ever really been in!” Before she died last November, she affirmed that Hepburn was a lesbian.

“I was pleased that she went on the record about Hepburn because I don’t think she’d ever done it before,” says Tyrnauer. “It really provides a great assist to Scotty’s narrative about Hepburn and Tracy, because people are in willful suspension of belief about this supposed golden couple.”

Even more startling are Bowers’ lusty tales about Wallis Simpson and Edward VIII. “Wally and Eddie,” corrects Bowers, waving away their formal names. “It was very easy to see how she talked him out of being king of England because she had complete control over him,” says Bowers. “She told him if you want to fool around and do this and that, you can’t do it if you’re king.”

Scotty Bowers at home in LA. Photograph: Courtesy of Greenwich Entertainment

“A lot of people don’t believe that particular story,” says Tyrnauer. “But he places them at the Beverly Hills Hotel in the 50s. We found a picture of them in the Beverly Hills Hotel in that period – it’s in the movie.” Four former clients knew Edward, and the couple’s close friend, photographer Cecil Beaton, titled an entire chapter of his diary: “Scotty.”

“There were many, many factors that connected them,” says Tyrnauer. “I cross-referenced everything I could.” When Bowers described a mansion’s winding pathway to the pool house, or a gate in a backyard, Tyrnauer would pull up an aerial view of Google Maps and there it was, as though the nonagenarian had visited yesterday.

In Los Angeles, notes the director: “You can wipe the dust off something that has been obscured and find the truth. Scotty’s a living example of that. Here he was in Laurel Canyon for decades minding his business. And yet he’s Scotty Bowers, the infamous male madame to the stars, and either you knew it or you didn’t.”

He has tried to ensure Scotty and the Secret History of Hollywood tells the truth instead of peddling innuendo like tabloids, TMZ, or even acclaimed smut such as Kenneth Anger’s Hollywood Babylon.

“Am I in that, too?” asks Bowers.

Tyrnauer chuckles: “Maybe between the lines.”

“There always will be secret life happening,” beams Bowers. “People should do what pleases them and the other person – some people just please more than a few.”

• Scotty and the Secret History of Hollywood is out now in the US and awaiting a UK release date