Graspop have basically said it's nonsense that Sabbath are playing there.
Quote: "Studio Brussel has news for you: apparently Black Sabbath is coming to Graspop Metal Meeting next summer.How nice of them to let us know! Perhaps Studio Brussel can reveal a few other names even we don’t know about? No, seriously, Graspop Metal Meeting is the only channel for official GMM communications"
16/9 Richie Kotzen