"Please don't cry, or my heart will break when I go on my way," Greek singer Demis Roussos sang in one of his most famous hits, "Goodbye My Love, Goodbye."

The 68-year old, equally famous for songs including "Forever and Ever" and "Quand je t'aime," died on Sunday morning at the Hygeia Hospital in Athens, the BBC reported.

Artemios Ventouris Roussos was born June 15, 1946, in Alexandria, Egypt. When his parents, who were of Greek and Italian descent, lost their possessions during the Suez Crisis, they decided to move to Greece, GreekReporter noted. There, Roussos participated in various bands, starting with The Idols at age 17.

Roussos rose to fame in 1968 as a vocalist and bassist for "Aphrodite's Child," and his unique vocal style helped launch the band's international career. The progressive rock group, which also included Vangelis, sold over 60 million albums worldwide.

In the 1970s, the singer went on to have a successful solo career. With his 1973 hit "Forever And Ever," he topped the charts in several countries, a feat he also accomplished in the United Kingdom in 1976. He is also known for his vocal adaptation of the score of the 1981 film "Chariots of Fire," composed by Vangelis.

In 1985, Roussos was part of a hijacking incident when members of Hezbollah and Islamic Jihad took over TWA Flight 847, on which he was traveling from Athens to Rome, the Daily Mail recalled. He and his third wife were held as prisoners in Beirut for five days but were eventually released.

The singer's final public appearance occurred in 2013 in Athens, when he received the French Legion of Honor for his life's work. On Monday, Vangelis said he was "shocked" to learn Roussos' death came "so soon."

"Nature gave you this magic voice of yours which made millions of people around the world very happy," Roussos' "Aphrodite's Child" bandmate wrote. "As for me, I keep those special memories that we share together those early days and I wish you to be happy wherever you are."

Greek singer Nana Mouskouri, meanwhile, recalled Roussos' "superb voice" on French radio RTL

"He traveled in the world. ... He loved what he was doing," she said. "He was an artist, a friend. I hope he is in a better world."