(CNN) A British woman was saved by the Croatian Coast Guard after spending what she said was close to 10 hours treading water overnight in the Adriatic Sea after falling off a cruise ship.

Kay Longstaff spoke to Croatian news outlet HRT shortly after arriving back on land.

"I fell off the back of the Norwegian Star," said the woman, who lives in Spain, according to her Twitter account. "I was in the water for 10 hours, so these wonderful guys rescued me. I'm very lucky to be alive."

Longstaff, 46, was then led by medical personnel to an ambulance.

Lovro Orešković, the captain of the ship that rescued her, told local media that it was a "miracle" that she survived.

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