It's being discussed on QOL and also on various German boards:
Who could be the mysterious "surprise headliner" of Rock am Ring and Rock im Park festivals in June after Limp Bizkit cancelled?
All they say is that the band is an all time popular band in Germany and that they fit the 20th anniversary of the festival. And Marek Lieberberg are Queen's German concert agent...
Could it be Queen + PR?
Wouldn't it be typical of the secrecy with which the current QPR tour was "promoted" that 3 weeks before the event the name is not out? Should we save more money?
Black sabbath- they're playing Donington, they'd fit the bill at Rock Am Ring. Almost sure.
Sorry, but can't imagine ppl there enjoying These Are The Days... or BoRhap with a video screen, sorry...