NEW YORK (CNN) -- Michael Gates Gill was a high-flying, six-figure-earning advertising executive years ago before he was abruptly fired. He had created huge campaigns for companies like Christian Dior and Ford and lived an even bigger life, with luxury automobiles, lavish vacations and fabulous clothes.

Michael Gates Gill's book about how working at Starbucks changed his life became a bestseller.

These days, however, he's traded his $3,000 Brooks Brothers suits for khakis and a green apron; the big bucks for a $10 an hour job as a barista at Starbucks. But Gill says he couldn't be happier.

"Losing my job turned out to be a gift in disguise."

After 26 years at J. Walter Thompson, a leading advertising agency, the then 63-year-old Gill was invited to an early breakfast and was told that he was getting the boot. He made too much money. Someone younger would work for less, he was told.

"Never go out to breakfast," he warns before bursting into laughter. "It's like the Mafia. You will never return." Watch the happy barista »

He can joke about it now, but Gill says he was devastated by his firing.

"I remember walking outside and bursting into tears," he says over a steaming cup of coffee at his current place of employment, a Starbucks in Bronxville, New York. "I was stunned. I knew that that part of my life was over."

That was just the start of a terrible reversal of fortune. In a few short years, Gill, the Yale-educated son of the famed New Yorker writer Brendan Gill, closed the consulting business he started after he was laid off, got divorced and was diagnosed with a brain tumor. He had hit both the rock and the bottom and was continuing to fall.

A trip to Starbucks would irrevocably change his life, he says. Unbeknownst to him, the coffee shop was holding a hiring fair the morning he walked in for his daily dose of caffeine. A manager approached him and asked if he would like to apply for a job. Without thinking, he said yes.

That was five years ago. These days, when the divorced father of five is not whipping up a caramel macchiato or perfecting his latte foam, he's sweeping floors and scrubbing toilets.

"I still have trouble with some of the drinks," he admits, "but I'm a good cleaner.... I can make a toilet shine like a Ferrari."

If life continues on an upswing for Gill, he may one day be able to purchase a Ferrari. His memoir, "How Starbucks Saved My Life," became a New York Times bestseller. The actor Tom Hanks has plans to produce and star in the film version. Gus Van Sant has agreed to direct.

"When I lost my job I thought my life was over," he says. "I didn't realize it was just the beginning." He smiles contentedly and declares, "I may have a part-time job, but I have a full-time life."

He is also sharing everything he has learned, hitting the lecture tour with his "uplifting tale of personal transformation."

Home for Gill is now a modest apartment in the attic of an old house about five minutes away from the 25-room mansion where he was raised.

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