Ozzy Osbourne has filed a lawsuit against venue owners and promoters AEG, and he wants other artists to join him in a class action.

It’s an escalation of a dispute that surfaced after his wife and manager, Sharon Osbourne, accused AEG of “blackmail” and “strong-arm” tactics in forcing Ozzy to perform in a venue against his will.

The argument centers on a clause in an AEG contract stating that if Osbourne wishes to perform at London’s O2 Arena during his upcoming farewell tour, then he must also play the Staples Center in Los Angeles – which he doesn’t want to do. The “block-booking” clause appears to be the result of AEG competitor Live Nation creating a similar clause connecting New York’s Madison Square Garden to the L.A. Forum.

Rolling Stone reports that Osbourne's suit accuses AEG of “anti-competitive conduct” via the “Staples Center Commitment” after he tried to book the O2 in February 2019. “AEG said it was available – but only on the condition that Ozzy be bound by the Staples Center Commitment," the document reads. "Sharon Osbourne … publicly complained about having to sign the Staples Center Commitment, but AEG would not relent.” It says elsewhere that Ozzy was left with “no choice at all” but to sign the Staples Center Commitment because “for a major artist such as Ozzy, there is simply no substitute for the O2 Arena when booking the London leg of an international tour.”

“This suit is without merit and we will vigorously fight it," AEG CEO Jay Marciano told Rolling Stone: "We welcome a closer look at the global live entertainment market and, specifically, our practices and the practices of our competition. AEG has always worked hard to put artists first. At the same time, we must respond to the actions of those we compete with, specifically Live Nation and Madison Square Garden. Fighting for a level playing field is fair competition at its core.”

Osbourne has asked for class action status so that “similarly situated artists” can take part in the lawsuit.