Olivia Wilde must be pretty red in the face right now.
The 27-year-old actress had an embarrassing gaffe on Saturday when she was Tweeting to promote her movie, "Cowboys & Aliens."
"Cowboys screening for 8,000 in the Piazza Grande a the Locarno Fest tonight," she wrote. "Prepping my speech in Swiss, Italian, and Apache just in case."
Only problem? "Swiss" isn't a language, as her followers soon let her know.
To her credit, Wilde acknowledged the mistake.
"Oh good, turns out there's no Swiss language," she responded. "That makes things simpler. I'll throw in Cantonese just to keep things interesting."
But to make matters worse, Wilde's mother is a "60 Minutes" producer, her father's a journalist and she went to all the best schools. Shouldn't she know better?
From Wilde's "oops" to Nikki Minaj's wardrobe malfunction to Ann Curry's graduation gaffe, let us know: Who had the most embarrassing celeb moment?