A memoir, "Peeling Onions," of his life as a child and young man is scheduled for publication this fall. In the past, the Nobel Prize-winning writer had revealed only that he had been in the Army, had been wounded and taken prisoner by the U.S. military, the BBC said.
"My silence over all these years is one of the reasons I wrote this book," he told the Frankfurter Allgemeine Zeitung. "It had to come out, finally."
The SS or Schutzstaffel, led by Heinrich Himmler, began as Hitler's personal body guard and grew into an elite military body with more than a million members. The Waffen SS, the combat section, was declared a criminal organization after the war.
Grass said that he received a call-up notice in 1944 after a year in a labor battalion. At the time, he did not think of the Waffen SS as "something frightful," he said, but later he was "burdened" by shame, the BBC reported.