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That was fast! Just three weeks after she got engaged to tennis player Ryan Sweeting, Kaley Cuoco has already slipped on a wedding gown.

Relax fans, the "Big Bang Theory" actress was actually in costume for her new movie, "The Wedding Ringer."

"It's my wedding day!!!!!" she teased, posting a picture of herself wearing a lace wedding dress and veil while eating yogurt.

Kelly Cuoco Engaged to Ryan Sweeting

It was accompanied by the hashtag "#fakeweddingcalmdown."

Cuoco's real wedding to Sweeting, 27, who proposed at the end of September, won't be for a while.

"We are too busy to wedding-plan," Cuoco, 27, told reporters on the red carpet at the 2013 Veuve Clicquot Polo Classic event in October. "In a year we will start talking about it. We are enjoying being engaged."