Greek pop singer Demis Roussos, who sold more than 60 million albums over the course of a stellar career that started as singer for progressive rock band Aphrodite’s Child in the 1960s and became a solo singer of hit serenades including “Forever and Ever,” “Goodbye” and “Quand je t’aime,” has died in Athens. He was 68.

The Hygeia Hospital in Athens said Roussos died following a lengthy hospitalization, but did not give an exact cause.

Born in Alexandria, Egypt, To a Greek father and an Egyptian mother of Italian origin, Artemios (later shortened to Demis) Ventouris Roussos grew up in the ancient port city, known as a musical melting pot, before his family moved to Greece in the early 60s. There Roussos at 17 joined a band called the Idols and met his future Aphrodite’s Child bandmate Vangelis Papathanassiou.

Vangelis, whose score for the film “Chariots of Fire” won him an Oscar in 1982, was among the first to pay tribute to Roussos after his death in a post on his website.

“Nature gave you this magic voice of yours, which made millions of people around the world very happy. As for me, I keep those special memories that we share together from those early days, and I wish you to be happy wherever you are,” it read.

Aphrodite’s Child produced three albums, including “It’s Five O’Clock” and “The Apocalypse of St. John,” which did well in Europe during the late 1960s, especially in France and the U.K.

Afterwards Roussos moved out of Greece and embarked on a solo career that made him an international household name, starting with “Forever and Ever,” which topped the charts in several countries in 1973, followed by ”My Friend the Wind,” ”Velvet Mornings,” ”Someday Somewhere,” and “Lovely Lady of Arcadia,” among others.

He once boasted to the Guardian that in 1975 he had five albums in the top 10 in the U.K. charts simultaneously.

Roussos’ other solo hits, which he mostly crooned in his signature high-pitched style, include “My Reason,” “Someday Somewhere,” and “Happy to Be on an Island pin the Sun.”

A charming rotund bearded man, famous for the colorful outfits he wore on stage — especially his kaftans — Roussos considered both Mozart and Sting among his favorite composers.

In 1985, after semi-retiring to Malibu, he spent his 39th birthday captive on an airplane plane as one of the 153 people taken hostage when two Shiite Muslim militiamen hijacked a TWA Boeing 727 on a flight from Athens to Rome. Five days later, when he was released unharmed in Beirut, Roussos thanked his captors for giving him a birthday cake and a guitar so he could sing.

In subsequent interviews Roussos described that experience as a life-changer that prompted him to start making music again. Shortly afterwards he released an album titled “The Story of Demis Roussos.”

Information on survivors was not immediately available.