(US Weekly has a close-up photo of the wardrobe malfunction.)
While watching the race later, Keibler covered the romper with a dark jacket. "So close to all the action!" she tweeted.
She also spent her time on the French Riviera drinking with royalty.
"Heading 2 the palace for cocktails w Prince Albert & Princess Charlene," she wrote Monday.
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Photographers spotted Stacy Keibler in Monaco for the Grand Prix race wearing a bright red romper. But unfortunately for the 33-year-old actress and model, cameras also caught her tiny pink thong peeking through the side of her outfit where a zipper had come undone.
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