He was a regular on German TV music shows, and in 1972 appeared in a film, Heut hau'n wir auf die Pauke.

[1] In 1975, Marcus took part in the German Eurovision selection with the song "Ein Lied zieht hinaus in die Welt".

Unusually in 1976, however, they organised a five-song final in which Marcus participated with "Chansons pour ceux qui s'aiment" ("Songs For Those Who Love Each Other").

He won the selection, so went forward to the 21st Eurovision Song Contest which was held on 3 April in The Hague, where "Chansons pour ceux qui s'aiment" fared less well than expected, placing 14th of the 18 entries.

[4] According to his manager and longtime companion Nikolaus Fischer, he died of the disease in the middle of May 2018 in Munich, a few weeks shy of his 70th birthday.