Back in March, Ozzy Osbourne filed a lawsuit against AEG, claiming concert agency is "blackmailing" him. The singer has alleged that AEG is using a practice called "block-booking" to force him to perform at the Staples Center in Los Angeles against his wishes.

Ozzy had tentatively agreed to perform at London's O2 Arena on February 11th, 2019 as part of his No More Tours 2 farewell run, but he claims that AEG added a provision stating that if Osbourne played an indoor arena within 25 miles of Los Angeles that was promoted by competitor Live Nation during the tour, he would have to play the AEG-owned Staples Center as well.

Ozzy feels this is effectively a violation of the antitrust laws, which prohibit businesses from gaining a stranglehold on customers.

"Sharon Osbourne, Ozzy's wife and business manager, publicly complained about having to sign the Staples Center Commitment, but AEG would not relent," the complaint reads. "Ozzy commences this action (on his own behalf and for all similarly situated artists) to prohibit AEG from enforcing the Staples Center Commitment, an unlawful tying arrangement that unfairly leverages AEG's dominance in greater London to distort and deter competition in greater Los Angeles."

Osbourne wanted judge to invalidate the provision in his contract that forces him to perform at Staples. According to Hollywood Reporter, a judge rejected a bid by AEG to stop Ozzy from pursuing an antitrust lawsuit earlier this week.

"AEG argues that Ozzy was free to play anywhere he liked in Los Angeles as long as he did not use Live Nation as his promoter to do so," writes U.S. District Court Judge Dale Fischer. "As Ozzy points out, this take on the allegations doesn't necessarily make AEG's actions less anticompetitive. But it is arguably different from what is pleaded in the complaint. … In any event, it is clear that the complaint alleges that Ozzy personally suffers damage in a fairly direct and non-speculative way by not being able to play in his preferred venues and that the damage stems from the kind of conduct that antitrust law is intended to prevent. AEG is alleged to be using market power in one market to foreclose competition in another through a tying arrangement. That tie allegedly harms Ozzy by constricting his choices on where to play his concerts regardless of whether Ozzy's or his concert promoter's name is on the contract with the venue."

Fischer also rules that Osbourne has adequately alleged he's been coerced. No matter what the exact restraint on him and the possibility Osbourne may have had a route toward playing his preferred venue, the judge again cites the push to get him to drop his promoter.

The judge also says the complaint sufficiently defines the relevant market — venues capable of hosting his shows — for antitrust purposes.

"Finally, a plaintiff does not need to show anticompetitive effects in a per se tying case, but Ozzy has nonetheless made numerous plausible allegations of how competition is harmed, most obviously through the restriction of competition in the tied market," Fischer continues in addressing one last argument from AEG.

Earlier in the year, Ozzy's wife and manager Sharon shared a a fiery letter she sent to AEG in which she condemned the act that would force the rock icon to perform at the Los Angeles venue as part of a deal for a scheduled concert at the O2 Arena.

She wrote: "Shame on AEG for bringing artists into a power struggle you're having with your competitor, Live Nation. I can assure you that Live Nation would never strong-arm an artist into playing a venue they're not comfortable performing in."

AEG Live chairman/CEO Jay Maricano responded, "Dear Sharon, Thank you for your note. Please understand this dispute is between The Forum and Staples Center and we couldn't agree with you more — it should always be the artist's choice. We long for the days when artists and fans came first. PS — The other guys started this first!"

Sharon responded a day later, saying: "This is a staggering attempt to blackmail Ozzy into playing your venue in Los Angeles. It is also a complete abuse of bargaining power and not conducive to a free market."

Sharon threatened legal action against AEG if Ozzy's London date was not confirmed, adding: "I find the way you're conducting yourself and your company to be no more than childish playground tactics. I cannot be involved in a squabble between two venue owning promoters as my interests only lie 100 percent with Ozzy."