Yes. It would be tour of the year if both are playing full sets.

Crazy "Die Hard" of each band would balk at this idea, thinking that their favorite band is above this and better than the other (Bon Jovi is more relevant than Def Leppard, they just released a great new album! Def Leppard rocks harder than Bon Jovi even though the drummer has only 1 arm!), but that's all bollocks. It will be heaven for those who love melodic rock, never mind those who are big fans of both bands like me.