Question: Jimi Hendrix and Demis Roussos, have which mutual occupation?

Context paragraphs:
Jimi Hendrix: James Marshall "Jimi" Hendrix (born Johnny Allen Hendrix; November 27, 1942 – September 18, 1970) was an American rock guitarist, singer, and songwriter.  Although his mainstream career spanned only four years, he is widely regarded as one of the most influential electric guitarists in the history of popular music, and one of the most celebrated musicians of the 20th century.  The Rock and Roll Hall of Fame describes him as "arguably the greatest instrumentalist in the history of rock music".

Reflection (Demis Roussos album): Reflection is an album released in 1984 by Demis Roussos.

On écrit sur les murs: "On écrit sur les murs" (English: "We write on the walls") is a song by Demis Roussos from the album "On écrit sur les murs" (1988).  It was written by Romano Musumarra and Jean-Marie Moreau.  The song was adapted by Worlds Apart in 2007 and by Kids United in 2015 on the album "Un monde meilleur".  In two different years, les Enfoirés adapted that song & so did RAFFY in 2016.  The song had been rewritten as On Dessine Sur les Murs (WE draw on the walls); a Despicable Me minion version.

Aphrodite's Child: Aphrodite's Child was a Greek progressive rock band formed in 1967, by Vangelis Papathanassiou (keyboards), Demis Roussos (bass guitar and vocals), Loukas Sideras (drums and vocals), and Silver Koulouris (guitar).

Demis Roussos: Artemios "Demis" Ventouris-Roussos ( ; Greek: Αρτέμιος "Ντέμης" Βεντούρης-Ρούσσος , 15 June 1946 – 25 January 2015) was a Greek singer and performer who had international hit records as a solo performer in the 1970s after having been a member of Aphrodite's Child, a progressive rock group that also included Vangelis.

Nelly Mazloum: Nelly Mazloum (9 June 1929 - 21 February 2003), an Egyptian of Italian and Albanian origin, was an actress, choreographer, dancer, and teacher of ballet, modern dance, Egyptian folkloric dance, traditional oriental dance and the creator of the oriental dance technique.  She was a pioneer, in that she was the first to apply Egypt's traditional legacy of Folkloric Dances into a dramatised artistic form.  Known for her sense of humour, she was known in Egypt in the 1930s as a child prodigy and from the 1940syo the 1960s for her many appearances in Egyptian films, her folkloric shows on Egyptian TV, and her company the "Nelly Mazloum Arabic Troupe of Dancers".  She is mother of singer Demis Roussos with Albanian origin.

Forever and Ever (Demis Roussos album): Forever and Ever is an album by Greek singer Demis Roussos.  It was released in 1973 on Philips Records.  A greatly popular album, it also topped the international albums charts in Germany, Netherlands and Norway and was number 2 in Austria.

Didier Barbelivien: Didier René Henri Barbelivien (born 10 March 1954 in Paris) is a French author, lyricist, songwriter and singer.  Beginning in the 1970s, he wrote a number of successful songs for artists such as: Dalida, Johnny Hallyday, Michel Sardou, Daniel Guichard, Claude François, Gilbert Montagné, Sylvie Vartan, Patti Layne, Gilbert Bécaud, Enrico Macias, Demis Roussos, Mireille Mathieu, Hervé Vilard, Michèle Torr, C. Jérôme, Christophe, Julio Iglesias, Sheila, Nicole Croisille, Patricia Kaas, Eric Charden, Jean-Pierre François, Michel Delpech, Philippe Lavil, Elsa, Gérard Lenorman, Ringo, Garou, Corynne Charby, David and Jonathan, and Caroline Legrand among others.

Norbert Daum: Daum was born in Braunau am Inn.  He studied the violin, guitar, and piano as well as composition and conducting.  Between 1965 and 1971, he was a member of the beat band The Substitutes.  Since 1971, Daum has lived in Munich, where he met composer and producer Ralph Siegel, for whom he wrote orchestrations in countless productions.  As a freelancer, Daum wrote more than 3000 orchestrations and worked with numerous artists in all genres, varying from crossover and outright classical music to German folk music and with artists such as Vicky Leandros, Karel Gott, Demis Roussos, and Die Jungen Tenöre.  He arranged Gilbert Bécaud’s 1985 French chart success ‘Desiree’.  He also worked in film and television music.

The Roussos Phenomenon EP: The Roussos Phenomenon EP is a popular EP by Demis Roussos.

Supporting paragraphs: Jimi Hendrix Demis Roussos
Answer: singer