Christian Kellens has been an active figure on the Belgian and European scene in the post WW II era.

In 1949 and 1951, he plays with the big band of saxophonist Jack Sels, and later tours occupied Germany with a smaller band led by Sels, with Herman Sandy, Nick Fissette (tp), Jay Cameron (sax) Jean Fanis (p), Benoît Quersin (b) and Rudy Frankel (drs) .

Active on the international jazz scene, he appears, in France, on the album of the French pianist Henri Renaud "trio, sextet & all stars" (BMG 74321606382), recorded with Jean-Louis Chautemps (sax), René Thomas (gt), Benoît Quersin (b) etc...

He can be heard in 1955 on an album of the Christian Chevallier big band, titled "Formidable" (Colombia/EMI). In the band, one can find Bobby Jaspar and Sadi a.o.

In 1957, he plays in Cologne (Germany) with the Kurt Edelhagen Big band, and appears a.o. on the album "Kurt Edelhagen Presents", recorded 10-13 July 1957, Cologne, Germany (Polydor LPHM 46052).

He played at the Newport Jazz Festival in 1958 with the International Youth Band.

He played and recorded a.o. with Henri Renaud (F), Jack Sels, Sadi, René Thomas, Jacques Pelzer, Bill Coleman etc...

With Francy Boland (piano, composer/arranger) and Kenny Clarke (drums), he recorded the LP "The Golden 8" (Blue Note) with Jimmy Woode (Bass), Derek Humble (alto sax), Kari Drevo (tenor sax), Raymond Droz (alto horn), Dusko Gojkovich (Trumpet) and plays the baritone horn next to the trombone. This octet was to become the nucleus of the famous Kenny Clarke/Francy Boland Big band.
With the Kenny Clarke/Francy Boland Big band, he recorded the album "Now hear our meanin' ".

In 1959, Christian Kellens performed at the Comblain-la-Tour Festival (B).

Also active in France, he played with his fellow citizens Jacques Pelzer, René Thomas etc...but also appears a.o. on the album "Henri Renaud Sextet" (Vogue, 1959), with Jean-Louis Chautemps (sax), René Thomas (guitar), Benoît Quersin (bass) and Jacques David (drums).

Later he moved to Argentina, and more recently back to Belgium.

He also played (and used on recordings) several other instruments, such as valve trombone, baritone horn, tuba, etc...