Like any good spy story, it started with cocktails. Stanley Weiss first encountered Guy Burgess drinking in the lounge aboard the RMS Caronia in the summer of 1950. Weiss was returning to America after several years in Europe; Burgess was moving there as a British diplomat. Over the course of the journey and in the months that followed, the men became friends. Weiss was astounded by Burgess’s skills as a conversationalist, his easy charisma and his connections to the world’s most important people. But there was one thing Burgess didn't share with his new friend: his true identity as a double agent for the Soviets.

Burgess was a member of the infamous Cambridge Five, a group of British double agents including Harold “Kim” Philby, Donald Maclean, Anthony Blunt, John Cairncross and possibly others, who ostensibly worked in the upper echelons of their government but actually used their connections and access to spy for the Soviet Union. Like the other members of the spy ring, Burgess saw Western powers appease Hitler before engaging in war. To Burgess and his fellow spies, it seemed as if the Soviet Union was the only true stronghold against the advance of Nazism.

Recruited by Czech Communist Arnold Deutsch, the Cambridge Five were avowed Communists who either quit their membership in the party or never joined it in order to provide cover for their work. The tactic was so effective that Philby was actually appointed to head of the anti-Soviet section of MI6 (the British intelligence office) near the end of World War II. All the men stole documents from the British Foreign Office and intelligence agencies like MI5 and MI6, and several continued their work in America. According to a once-secret archive smuggled out of the Soviet Union by a defector, Burgess alone handed over 389 secret documents to the KGB in the first half of 1945, and another 168 four years later.

Burgess had an impeccable—and impressive—social pedigree. He owned a book signed by Winston Churchill and was friends with Churchill’s niece, Clarissa. He knew writers like W.H. Auden and E.M. Forster, the economist John Maynard Keynes, and officials in MI5 and MI6. Burgess talked to his new American friend about Beethoven and the American obsession with annual holidays. He inspired Weiss to enroll in Georgetown University’s School of Foreign Service, and became his most glamorous friend.

But Burgess was far from the suave, polished spy regularly seen in pop culture. He was regularly drunk, ostentatious and openly homosexual at a time when to be so was a crime. “Burgess appears to be a complete alcoholic and I do not think that even in Gibraltar I have ever seen anyone put away so much hard liquor in so short a time as he did,” said one MI5 representative in 1949. During Burgess’s time at the BBC, a superior complained about his exorbitant expenditures: “I realize that a certain amount of drinking at the bar is inevitable, but I cannot believe that it is not possible to do business with responsible [Members of Parliament] except at the bar.”

This extravagant drunkenness helped Burgess avoid suspicion, but it also led to indiscretions. He once dropped a pile of documents stolen from the Foreign Office when he was drunk, and even told Weiss that his coworker, Philby, was a spy—though Weiss didn’t recognize it as a revelation at the time, as he writes in his memoir, Being Dead is Bad for Business.

“He told me all about his job—the official duties of the Second Secretary at the U.K. Embassy. He made it seem very glamorous—endless parties and glamorous dignitaries,” Weiss recalled via email. But Burgess left out any talk of Communism or the Soviet Union, and Weiss never suspected he was a spy.

As the Cold War intensified, suspicions about spies grew on both sides of the Iron Curtain. In 1943, the U.S. Army’s Signal Intelligence Service began VENONA, a secret program to examine and decode encrypted Soviet communications. The messages took months to decode, but in 1949 an FBI cryptanalyst discovered that a member of the British Embassy was spying for the KGB. Maclean, they suspected, was the mole, and he was placed under MI5 surveillance in 1951. But Philby, who worked as British intelligence liaison to the FBI and CIA at the time, learned of the decryption and told Maclean and Burgess that they were both likely to be discovered soon. The two spies fled to Moscow in May 1951, confirming all suspicions held against them and causing outrage in the U.S.

In the week following the revelation of Burgess and Maclean’s identities, Weiss learned the truth from a newspaper. “I was absolutely shocked to see my friend Guy Burgess on the front page,” Weiss recalled. “I learned later that Guy had abandoned his vintage Lincoln Continental at a local Washington garage and had left his prized book autographed by Churchill at a friend’s place in New York.”

Despite his work for the U.S.S.R., the spies were never fully trusted by their handlers, and Burgess seems to have become unhappy in Moscow. Defection itself wasn’t a crime under English law. But as-yet-undiscovered spy Anthony Blunt warned Burgess that a trial would have disastrous results for the entire circle.

Burgess, it seemed, was trapped. He continued carousing in Russia, and was visited periodically by British reporters like Edward Crankshaw, who despised the spy’s treachery but later admitted that “I liked him much and finished up being deeply sorry for him. The man is half dotty, not actively vicious. The whole situation is the sort of personal tragedy that can only be ended by death.”

Death—and drinking—finally ended Burgess’s exile. He died of acute liver failure on August 30, 1963 at age 52. It was an ignominious end for one of Britain’s most notorious characters, but Burgess’s legacy (and that of the Cambridge Five) lived on in pop culture through stories like John LeCarré’s Tinker, Tailor, Soldier, Spy.

As for Weiss, he never forgot the spy who inadvertently shaped his life. “Guy Burgess did a lot for me at a very crucial time in my young life,” Weiss said. Burgess helped him through a bad breakup, suggested he attend college to become a diplomat, and introduced him to other diplomats—as well as gin and tonics.

“Guy Burgess opened up a whole new world and a new path in my life at one of my lowest moments,” Weiss said. “The actual memories I have of him are positive ones. I knew him when I was 24—there’s not much about my life that didn’t change pretty significantly after that point.