Tiny Tim, the eccentric ukulele-strumming performer best known for his quavering rendition of “Tiptoe Through the Tulips,” has died at the age of 66.

A nursing supervisor at Hennepin County Medical Center in Minneapolis said the entertainer went into cardiac arrest and died shortly after entering the hospital late Saturday. The official cause of death had not been established, she said.

The singer, whose real name was Herbert Khaury, had suffered a heart attack during a stage performance in Massachusetts Sept. 28.

Tiny Tim parlayed his trembling falsetto voice and unique appearance, which included long, stringy hair and baggy clothes, into a cult following in the late 1960s and early 1970s.

He was best known for the 1968 hit “Tiptoe Through the Tulips.” The next year, his nationally televised wedding to Victoria “Miss Vicky” Budinger was among the most watched programs in the history of Johnny Carson’s “Tonight Show,” although the marriage was short-lived.

He recently told a local talkshow that only 40% of his heart was still working after the September heart attack, but expressed optimism he could live for several more years.

He had given up touring after his heart attack and said he had applied for Social Security so he could support himself and his third wife, Sue.

He lived in his wife’s hometown of Minneapolis. She was with him when he died.

Follow @Variety on Twitter for breaking news, reviews and more