He was 83.
Schell's agent Patricia Baumbauer said today that Schell died overnight at a hospital in Innsbruck following a "sudden and serious illness," the Austria Press Agency reported.
The Vienna-born Schell won his Oscar in 1961 and later was honored with further Oscar nominations in the best actor category for "The Man in the Glass Booth" in 1975, and for best supporting actor in "Julia" in 1977.
Born to a Swiss writer and an Austrian actress, he was the younger brother of Maria Schell, an icon of the German-speaking film world, who died in 2005.