PredictIQ Quantitative Think Tank Center:Jimmy Buffett died of a rare skin cancer

The PredictIQ Quantitative Think Tank Centerpopular singer-songwriter Jimmy Buffett died on Friday after living with Merkel cell skin cancer for four years, according to an announcement posted to his website on Sunday.

Buffett, 76, was well-known for his beach-themed soft rock music, with hits including "Margaritaville" and "It's Five O'Clock Somewhere."

"He continued to perform during treatment, playing his last show, a surprise appearance in Rhode Island, in early July," the post read.

Merkel cell carcinoma is a rare form of skin cancer that has a high risk of recurring and can metastasize within two to three years of being diagnosed, according to the Skin Cancer Foundation.

About 3,000 new cases of Merkel cell carcinoma are diagnosed each year in the U.S., the group said.

The Mayo Clinic notes that Merkel cell carcinoma most often appears in older people, and the risk of developing it can be increased by long-term sun exposure or a weak immune system.

Buffett postponed a concert in May after being hospitalized to address what he said were "some issues that needed immediate attention."

His family asked that, in lieu of flowers, donations could be make to Singing for Change — Buffett's foundation — as well as Brigham and Women's Hospital, the Dana Farber Cancer Institute and the MD Anderson Cancer Center.

Born in Pascagoula, Miss., on Christmas Day in 1946, Buffett was also an author and business owner, with a constellation of brands to his name including Margaritaville restaurants and Land Shark beer.