Felgen started his career as a teacher. During the Second World War, Felgen was a translator for the German occupiers, and then a reporter with a French-language newspaper. He studied theater and opera in Brussels and Liège; in 1946, he joined Radio Luxembourg as a chorus singer and a French-language reporter. In 1949, the mastering of his baritone completed his theatre and opera studies. In 1951, he had his first internationalhit record, "Bonjour les amies". The song went on to become the theme song for his national broadcaster. In 1953, he recorded his first German-language record, "Onkel Toms altes Boot", in Berlin. He represented his home country in the Eurovision Song Contest 1960 with "So laang we's du do bast", becoming the first Luxembourger and the first male contestant to represent Luxembourg and the first participant to sing in Luxembourgish. He finished last with only one point. Two years later he entered the contest again, this time doing much better by finishing in 3rd place with the song "Petit bonhomme". He did at times do the commentary in German, too. One of the greatest hits of Felgen was "Ich hab Ehrfurcht vor schneeweißen Haaren", a cover of singer-guitarist and entrepreneur Bobbejaan Schoepen. Another was "Sag warum", in 1959, based on a melody by Phil Spector. Camillo Felgen also wrote German lyrics for cover versions of international songs, using the pseudonym Jean Nicolas. It is sometimes incorrectly stated that he also used the name "Lee Montague", but that was the pen-name of another person, Lawrence “Larry” M. Yaskiel, a Londoner who worked as a Sunday-school teacher and encyclopedia salesman before becoming involved in pop music in Germany in the 1960s, working first for Deutsche Vogue, then for various production companies, and for A&M Records, before retiring to the Canary Islands. As Jean Nicolas, Felgen also translated the only two songs recorded by The Beatles in German, "I Want to Hold Your Hand" and "She Loves You", in 1964. Felgen, then working as a programme director at Radio Luxembourg, was given just 24 hours to finalize the translated lyrics, fly to Paris, and coach the band on German phonetics.
