After a certain amount of rigmarole, she convinced Facebook that she was legitimate and had her account reinstated with an apology.
Several other Kate Middletons reported similar experiences.
Facebook executives said some mistakes were inevitable as they tried to keep the social network secure.
Middleton has high hopes that this season of silliness will end once her famous namesake is actually married on April 29.
"Soon she'll be Princess Catherine or Princess Kate and I can just be plain old Kate Middleton again," she said.
"Fingers crossed. Otherwise I might cry."
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