Russian opera singer Anna Netrebko is suing New York City's Metropolitan Opera, after she was dropped following Russia's invasion of Ukraine.
The internationally renowned soprano is suing the opera house and its manager for $360,000 in damages.
Ms Netrebko has previously supported President Vladimir Putin - but did condemn the invasion after pressure from the Met.
The opera has responded in a statement, saying the lawsuit had no merit.
Opera star Ms Netrebko's lawsuit - against both the Met and its manager, Peter Gelb - was filed in the US District Court in Manhattan on Friday.
She is alleging defamation, breach of contract and other violations, and is demanding hundreds of thousands of dollars in damages for lost performance and rehearsal fees.
The 51-year-old claims the Met caused her "severe mental anguish and emotional distress", including "depression, humiliation, embarrassment, stress and anxiety, and emotional pain and suffering".
Ms Netrebko, who also has Austrian citizenship, has previously expressed support for President Putin. In 2014, she donated money to a theatre in the rebel-held city of Donetsk in eastern Ukraine, and was pictured holding a pro-Russian rebel flag.
After Russia invaded Ukraine in February 2022, she was urged to speak out against Mr Putin and the war.
She did eventually accede to the demands to condemn the conflict - but stopped short of denouncing the Russian president and was dropped by the Met in all future performances a month after the invasion.
Her lawsuit alleges that the Met and Mr Gelb "harmed Netrebko's relationship among audiences, including by encouraging protests against her performances", and that her criticism of the war lost her contracts with Russian theatre companies, AP news agency reported.
The Met said in a statement: "Ms Netrebko's lawsuit has no merit."
Earlier this year, Ms Netrebko filed a separate complaint through the union representing opera performers, the American Guild of Musical Artists.
An arbitrator in that dispute ruled in February that the Met had violated a contractual agreement when it cancelled some performances, and awarded her compensation more than $200,000.
Since being dropped by the Met - who she had been singing with for 20 years - Ms Netrebko has performed elsewhere including in Italy in June, and is scheduled for upcoming performances in Buenos Aires, Berlin, Vienna, Milan and Paris.
She is also due to perform in Prague in October, but last month the city's deputy mayor urged the concert hall to cancel the show.
Jiri Pospisil said he had met with Ukrainian officials and said Ms Netrebko was on Ukraine's sanctions list. The producer organising the event said Ms Netrebko had condemned the war and she did not understand efforts to cancel the event, which is almost sold out.