Fans were not happy when pop superstar Beyonce showed up to help celebrate the 50th anniversary of the Country Music Awards' with a secret and boisterous performance of her song "Daddy Lessons" with the Dixie Chicks.

Beyonce hit the stage unintroduced when the show was about two-thirds over Wednesday, wearing multiple strands of pearls and a sheer, champagne-colored body-hugging dress. She looked happy and comfortable, dancing and clapping. The performance got a standing ovation.

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"Daddy Lessons," on her recent album "Lemonade," is as close to a country song that Beyonce's ever released. The Dixie Chicks started covering the song on tour earlier this year.

Not everyone was prepared to welcome Beyonce with open arms. "Let me have my country music in peace" wrote one critic on Twitter. Another suggested that whoever had invited her should be fired.

It wasn't just Beyonce's appearance that caused anger — some country music fans have disliked Dixie Chicks since band member Natalie Maines criticized former U.S. President George W. Bush over a decade ago.

The Associated Press contributed to this report.