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Carrie Underwood says she is mortified after making a sex joke about Matthew McConaughey at Sunday's ACMAs.

Before presenting Underwood with Entertainer of the Year, McConaughey told the audience how George Strait's boots once got him "lucky."

After collecting her trophy from him, Underwood was at a loss for words and blurted out: "I don't know what to say. I got nothin' ... I want to see those boots, Matthew."

Camila Alves - the mother of McConaughey's 8-month-old son Levi - was sitting in the audience.

Now, Underwood tells Fox News, "I'm so embarrassed, I totally embarrassed myself. I just blanked. You want to say something eloquent in a moment like that and I embarrassed myself."

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"I'm sorry Matthew, I'm sorry to my family," she says. "I'm totally embarrassed."

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Underwood wasn't too razzled: She still managed to mention her boyfriend, Ottawa Senators hockey player Mike Fisher, in her acceptance speech.

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"Mike, baby, I wish you were here!" she said.