Klavs has played with almost everybody on the danish jazz-scene and toured with Ernie Wilkins Almost Big Band, Horace Parlan and Toots Thielemans, Lee Konitz, John Abercrombie, Pierre Dørge, Svend Asmussen and many, many others.
Klavs was the steady bassplayer with gospel and jazz singer Etta Cameron from 1979 until her death in 2010.
For many years Klavs has worked and lived together with percussionplayer, drummer and composer Marilyn Mazur. He was a member (throughout the 20 years of existence) of her international group FUTURE SONG, which she formed in 1989 after leaving Miles Davis Group.
He now plays with Marilyn Mazur Group – a quartet with Fredrik Lundin and Krister Jonsson.
Makiko Trio with japanese pianoplayer Makiko Hirabayashi and Marilyn Mazur on drums has recorded 3 albums for the german label Enja and toured in Europe and Japan since 2005.
Has recorded with Etta Cameron, Marilyn Mazur, Horace Parlan, Savage Rose, Putte Wickman, Pierre Dørge, Makiko Hirabayashi and many others.