Scott McKenzie, who sang the 1960s hit San Francisco (Be Sure To Wear Flowers In Your Hair), has died aged 73.
The singer was a close friend of Mamas and Papas star John Phillips, who wrote and produced the San Francisco track.
Released in May 1967, it became a global hit and an anthem for the 1960s counterculture movement.
"I am amazed at how San Francisco continues even now to evoke dreams in the hearts and minds of people all over the world," McKenzie wrote in 2002.
He was found by a neighbour in his home on Sunday afternoon. His death was confirmed by another neighbour, Victoria Byers.
She told the BBC he had been in and out of hospital recently after falling ill with Guillain-Barre Syndrome, a disease affecting the nervous system.
"I think he had a heart attack this most recent time. He was in the hospital," she said. "They did not want him to leave the hospital, but he wanted to be in his house [when he died]".
Born Philip Wallach Blondheim in January 1939, the singer, songwriter and guitarist grew up in North Carolina where he lived with his grandparents while his widowed mother worked in Washington DC.
As a teenager, he met Phillips and formed a doowop band called The Abstracts. The band moved to New York and became The Smoothies, where they played on the club circuit and recorded two singles.
It was at this stage in his career that he changed his name, after complaints that Blondheim was unpronounceable, and comments by comedian Jackie Curtis that he looked like a Scottie dog - hence Scott.
With the rise of folk music in the 1960s, he and Phillips approached banjo player Dick Weissman and went on to form The Journeymen. The trio recorded three albums, before breaking up in 1964.
Phillips went on to form the original The Mamas and Papas and is credited with writing a memorable body of songs that chronicled the personal and social upheavals of the decade.
McKenzie declined an invitation to join him in favour of becoming a solo star, but the two remained close friends.
San Francisco (Be Sure To Wear Flowers In Your Hair), penned by Phillips and featuring him on guitar, was McKenzie's only significant hit.
Inspired by the first Monterey Pop Festival, which organised by Phillips and Lou Adler, among others, it was reportedly recorded with McKenzie wearing a flower garland and friends gathered on the floor to meditate.
It soared to the number four spot in the US Billboard 100, and number one in the UK.
McKenzie released two solo albums, before dropping out in the late 1960s and moving to Virginia Beach, after struggling with the pressures of fame.
'Summer of love'
Over the course of his career, he dedicated every American performance of the track to Vietnam veterans, and in 2002 sang at the 20th anniversary of the dedication of the Vietnam Memorial Wall.
He returned to music in the late 80s when he replaced first Denny Doherty, and then an ailing Phillips, in a touring version of The Mamas and the Papas.
He also co-wrote the Beach Boys hit Kokomo.
"Never before or since, with the exception of rap, has popular music contained such sheer poetic and social power," wrote McKenzie on his website in 2002.
"Even at the end of the decade, when so many of us had lost hope, when the summer of love had turned into a winter of despair, our music helped keep us alive and carry us forward into a world we had hoped to change.
"And so it still does."