Jimmy Buffett’s cause of death has been revealed, just days after the singer-songwriter passed away.

A statement posted to the “Margaritaville” singer’s website said Buffett, who was 76, “passed away peacefully on the night of September 1st surrounded by his family, friends, music and dogs.”

An obituary posted to that same website said Buffett had been fighting Merkel cell skin cancer for four years, and had been continuing to perform during treatment. It progressed into lymphoma, sources told TMZ, and Buffett had reportedly been receiving hospice care.

Merkel cell carcinoma is a rare type of skin cancer, according to Mayo Clinic. It typically appears as flesh-colored or bluish-red nodules on your face, head, or neck. Merkel cell carcinoma can grow fast and spread quickly, and is often seen in older people with a weakened immune system or after long-term sun exposure.

Buffett announced in May that he had “wound up back in the hospital” after a check-up in Boston. He did not say at the time what medical issue he was dealing with, but remained light-hearted, telling fans: “Growing old is not for sissies, I promise you. I also will promise you, that when I am well enough to perform, that is what I’ll be doing in the land of She-Crab soup.”

He played his last show, a surprised appearance in Rhode Island, in early July, according to his obituary.

In lieu of flowers, Buffett’s family has asked that donations be made to his foundation, Singing for Change; Brigham and Women’s Hospital; the Dana Farber Cancer Institute; or the MD Anderson Cancer Center.

James William Buffett was born on Christmas day 1946 in Pascagoula, Mississippi, and raised in the port town of Mobile, Alabama. He graduated from the University of Southern Mississippi in Hattiesburg, Mississippi, and went from busking the streets of New Orleans to playing six nights a week at Bourbon Street clubs.

He released his first record, “Down To Earth,” in 1970 and issued seven more on a regular yearly clip, with his 1974 song “Come Monday” from his fourth studio album “Living and Dying in ¾ Time,” peaking at No. 30. Then came “Margaritaville.”

“Margaritaville,” released on Feb. 14, 1977, quickly took on a life of its own, becoming a state of mind for those ”wastin’ away,” an excuse for a life of low-key fun and escapism for those “growing older, but not up.”

The song is the unhurried portrait of a loafer on his front porch, watching tourists sunbathe while a pot of shrimp is beginning to boil. The singer has a new tattoo, a likely hangover and regrets over a lost love. Somewhere there is a misplaced salt shaker.

“What seems like a simple ditty about getting blotto and mending a broken heart turns out to be a profound meditation on the often painful inertia of beach dwelling,” Spin magazine wrote in 2021. “The tourists come and go, one group indistinguishable from the other. Waves crest and break whether somebody is there to witness it or not. Everything that means anything has already happened and you’re not even sure when.”

The song — from the album “Changes in Latitudes, Changes in Attitudes” — spent 22 weeks on the Billboard Hot 100 chart and peaked at No. 8. The song was inducted into the Grammy Hall of Fame in 2016 for its cultural and historic significance, became a karaoke standard and helped brand Key West, Florida, as a distinct sound of music and a destination known the world over.

“There was no such place as Margaritaville,” Buffett told the Arizona Republic in 2021. “It was a made-up place in my mind, basically made up about my experiences in Key West and having to leave Key West and go on the road to work and then come back and spend time by the beach.”

The song soon inspired restaurants and resorts, turning Buffett’s alleged desire for the simplicity of island life into a multimillion brand. He landed at No. 13 in Forbes’ America’s Richest Celebrities in 2016 with a net worth of $550 million.

Music critics were never very kind to Buffett or his catalogue, including the sandy beach-side snack bar songs like “Fins,” “Come Monday” and “Cheeseburger in Paradise.” But his legions of fans, called “Parrotheads,” regularly turned up for his concerts wearing toy parrots, cheeseburgers, sharks and flamingos on their heads, leis around their necks and loud Hawaiian shirts.

“It’s pure escapism is all it is,” he told the Republic. “I’m not the first one to do it, nor shall I probably be the last. But I think it’s really a part of the human condition that you’ve got to have some fun. You’ve got to get away from whatever you do to make a living or other parts of life that stress you out. I try to make it at least 50/50 fun to work and so far it’s worked out.”

His special Gulf Coast mix of country, pop, folk and rock added instruments and tonalities more commonly found in the Caribbean, like steel drums. It was a stew of steelpans, trombones and pedal steel guitar. Buffett’s incredible ear for hooks and light grooves were often overshadowed by his lyrics about fish tacos and sunsets.

Rolling Stone, in a review of Buffett’s 2020 album “Life on the Flip Side,” gave grudging props. “He continues mapping out his surfy, sandy corner of pop music utopia with the chill, friendly warmth of a multi-millionaire you wouldn’t mind sharing a tropically-themed 3 p.m. IPA with, especially if his gold card was on the bar when the last round came.”

Buffett’s evolving brand began in 1985 with the opening of a string of Margaritaville-themed stores and restaurants in Key West, followed in 1987 with the first Margaritaville Café nearby. Over the course of the next two decades, several more of each opened throughout Florida, New Orleans and California.

The brand has since expanded to dozens of categories, including resorts, apparel and footwear for men and women, a radio station, a beer brand, ice tea, tequila and rum, home décor, food items like salad dressing, Margaritaville Crunchy Pimento Cheese & Shrimp Bites and Margaritaville Cantina Style Medium Chunky Salsa, the Margaritaville at Sea cruise line and restaurants, including Margaritaville Restaurant, JWB Prime Steak and Seafood, 5 o’Clock Somewhere Bar & Grill and LandShark Bar & Grill.

There also was a Broadway-bound jukebox musical, “Escape to Margaritaville,” a romantic comedy in which a singer-bartender called Sully falls for the far more career-minded Rachel, who is vacationing with friends and hanging out at Margaritaville, the hotel bar where Sully works.

Buffett also was the author of numerous books including “Where Is Joe Merchant?” and “A Pirate Looks At Fifty” and added movies to his resume as co-producer and co-star of an adaptation of Carl Hiaasen’s novel “Hoot.”

Buffett is survived by his wife, Jane; daughters, Savannah and Sarah; and son, Cameron.

The Associated Press, Dianté Gibbs and Jeremy Tanner contributed to this report.