Other solo hits include My Friend the Wind, My Reason, Someday Somewhere and Happy To Be On An Island In The Sun.
Roussos' fondness for kaftans saw him dubbed "the Kaftan King" and he often wore them for his performances on shows such as Top of the Pops.
He was also famous for his vocal adaptation of the score from the 1981 film Chariots of Fire, which had been composed by Vangelis.
In 1978 he decided to keep a lower profile and moved to Malibu Beach in the US.Plane hijack
On 14 June, 1985, Roussos boarded TWA Flight 847 from Athens to Rome - and found himself at the mercy of the Lebanese militant group Hezbollah, who hijacked the plane.
The men, who had smuggled a pistol and grenades through airport security, held the passengers at gunpoint.
The militant group demanded the release of 17 members of Hezbollah and the Iraqi Islamic Daawa Party, who had been detained in Kuwait for attacks that killed six people in 1983.
Roussos spent his 39th birthday in captivity, before being released in Beirut on 18 June - but most of the remaining 153 passengers spent 17 days on the plane.
Speaking to the Reuters news agency at the time, the singer said he had been "treated quite well".
"They gave me a birthday cake and they gave me a guitar, to sing," he said. "They have been very polite and very nice with us."Return to music
Over the years, his quote became misinterpreted and distorted. Some papers said he had serenaded the hijackers. Others claimed he had pledged allegiance to Hezbollah.
Roussos, who rarely spoke about the incident, admitted he was riled by the exaggerations in an interview with Australia's Daily Telegraph in 2006.
"It is not every day that a pop superstar gets involved with terrorism as a victim, so the press takes advantage of that to say things they think are funny.
''I would like to see the journalist [who first reported the claim] in front of gunpoint like I was. Believe me, if he was there he would be so scared he wouldn't care about writing such stupidities like that.''
The experience changed his life and afterwards he decided the best way he could help others and promote understanding in the world was by returning to music.
He released his album The Story of Demis Roussos not long after.