Up to 20,000 Canadians may have unknowingly lost their citizenship by failing to celebrate their 24th birthdays in Canada, the Canadian Broadcasting Corp. reported Wednesday.

An obscure provision in that nation's Citizenship Act — on the books from 1947 to 1977 — automatically stripped citizenship from Canadians who celebrated their 24th birthday outside the country within those dates without signing the proper form, CBC News said.

Now as Canadians rush to get passports to comply with regulations requiring them for entry into the United States, some are finding they are no longer Canadians in good standing.

Septuagenarian Barbara Porteous discovered last year while applying for a passport that she had lost her citizenship, CBC News reported.

Click here to read the Canadian Broadcasting Corp. story.

"These documents confirm you were a Canadian citizen, but you ceased being a Canadian citizen on June 14, 1960, the day following your 24th birthday," a letter from Citizenship and Immigration read.

"I cried for a couple of hours," Porteous told CBC News. "I mean, the hollowness you get inside when you find out that everything you live for is gone."

Porteous is part of a group called the Lost Canadians, a group that may be as large as 20,000 — many of whom have no idea that they've lost their citizenship.

The Canadian government has moved to fast track the reinstatement of citizenship for the Lost Canadians.

"We're trying to right the wrongs of the past and do the reasonable thing, the right thing, for what are essentially Canadians in all but name," Citizenship and Immigration Minister Diane Finley told CBC News.

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