The U.S. Open tennis competition is a celebrity-studded event every year.

Celebrities from Ben Stiller to Bill Clinton packed the Billie Jean King Tennis Center in Flushing Meadows, Queens to watch Serena play in her first round match.

An account linked to Choni Francis tweeted "#Beyoncé at the #USOpen" accompanied with a short clip of a woman wearing a black mask and her hair tied back in a low ponytail.

Not me getting confused for @Beyonce at the #USOpen tonight, then trending on Twitter while the internet laughs over the faux pas.

Cox had tweeted a video of herself getting ready for the evening just a few hours earlier, with Beyoncé herself providing the soundtrack. 

The song "PURE/HONEY" from Cox's most recent album Renaissance is playing as she walks to the mirror to straighten her dress and strikes a stance for the camera.

She admitted to Living for Beyoncé to Entertainment Tonight in 2020, saying that "everyone knows.

I make an effort not to worship earthly gods or goddesses, but I do worship Beyoncé.

Prior to that, she even impersonated Queen Bey for a legendary Lip Sync Battle performance of the classic song "Lose My Breath" by her girl group Destiny Child.

An account linked to Choni Francis tweeted "#Beyoncé at the #USOpen" accompanied with a short clip of a woman wearing a black mask and her hair tied back in a low ponytail.