Alec Rupen Costandinos, is a French composer, music producer, songwriter and singer of the 1970s, known for his contributions to disco music. His father was Armenian and his mother was Greek. Costandinos dominated the disco and Euro-disco genres in the late 1970s. He began his career as a publisher and producer for various artists, including French pop star Claude Francois and chanteuse Dalida. After writing Cerrone's "Love in C Minor", Costandinos was signed to Barclay Records. He released his first album, Love & Kisses in 1977, which featured the hit track "I Found Love". Costandinos went on to release a number of wildly successful records under the prominent American disco label, Casablanca. His album, Romeo & Juliet has been credited for bringing the concept album to dance music. He also wrote "Thank God It's Friday", the theme track to the disco film by the same name.
Costandinos was involved as a writer in the development of many productions of Demis Roussos. He also contributed to the debut album of Crystal Grass, which featured the club hit "Crystal World", released on the Philips label in France. He has also written under the pseudonym R. Rupen.