Héctor Omar Hoffmann Fenzel, better known as Sergio Denis (16 March 1949 – 15 May 2020) was an Argentine singer-songwriter and occasional actor.

In March 1969 he moved to Buenos Aires and entered the group "Los Bambis", and together recorded for the first time for Columbia Broadcasting System (CBS).

[1] This single began to have radio airplay in December, and on 1 January 1970 Denis first performed on TV, in the programme "Casino Philips", hosted by Andrés Percivale and broadcast by Canal 13 de Buenos Aires.

Once he returned to Argentina, he was enlisted to do the Servicio Militar Obligatorio, and assigned to the Batallón de Comunicaciones 181 in Bahía Blanca.

In 1972, due to the success of a song written by him, he co-starred in the film Me enamoré sin darme cuenta (I Fell in Love Without Noticing it) with Alicia Bruzzo and Luis Brandoni, directed by Fernando Siro.

He also recorded cover versions in Spanish of songs originally recorded in English, such as: California somnolienta (California dreamin', by The Mamas and the Papas) from the album Al Estilo de... Sergio Denis II (1981), Pipas de la paz (Pipes of peace, by Paul McCartney) included in the album La Humanidad (1984), Nada va a cambiar mi amor por ti (Nothing's Gonna Change My Love for You, by Glenn Medeiros) and Así fue nuestro amor (Annie's Song, by John Denver), both included in his album Afectos.

During most of his career, Denis had love affairs with famous women, such as actress/TV hostess Susana Giménez and actress/producer Cris Morena.

In 2007, Sergio Denis was dating a girl named Melisa Durán, when she was selected to participate in the TV programme Gran Hermano 2007 broadcast by Telefe.