LOS ANGELES, Calif. --

For most, the Fourth of July means a day off of work, flipping burgers and hanging out. But the holiday may have new significance for some celebrities. A handful of foreign-born stars have studied up on American history, been tested for citizenship, and passed with flying colors — red, white and blue!

Scottish-born comedian Craig Ferguson, host of “The Late Late Show With Craig Ferguson” on CBS, became a United States citizen in January 2008 when he passed the test with a perfect score.

“I took the test, the citizenship test, and it’s very difficult by the way. All you people born here, if you had to take that test, Canada would be building a fence right now,” he explained in his show.

“Baywatch” star Pamela Anderson is known throughout the world as the quintessential California beach girl, but the Canadian-born actress was granted U.S. citizenship in May 2008. She pledged her allegiance, not only so that she could vote, but also to help her four-legged friends. She intends to lobby against animal testing and, as she said on her Web site, “Crack the whip on Capitol Hill.” Sounds like “Legally Blonde” part three in the making!

Tracey Ullman was born in England, and after having a family and career in the States, she finally became a citizen in 2006.

“It’s a really interesting process…I went downtown, with thousands of other people, in the convention center. And you all wave flags, and give your green card in, and they showed a film - Moon landings and waving wheat fields and monster trucks…,” Ullman told the International Herald Tribune.

South African-born actress Charlize Theron became a U.S. citizen in May 2007, when she was sworn in with a crowd of over 5,000 people. On “The Late Show With David Letterman,” she said she did “incredibly well,” but was thrown off when she had to write the simple sentence, “It’s a sunny day.”

“It’s one of those weird feelings when you completely doubt yourself, and you’re like ‘does sunny have a double ‘N’?’” she told Letterman.

“The Silence of the Lambs” star Sir Anthony Hopkins was born in Wales, and when he became a citizen in April 2000, he reportedly celebrated with a 3,000-mile road trip across the country.

“America has been very generous to me, magnanimous really. I thought it would be good to give something back. It was a decision of the heart,” he told the BBC.

A Few Other Stars Who Have Pledged Their Allegiance:
Jim Carrey (Canadian)
Salma Hayek (Mexican)
Melania Trump (Slovenian)
Baseball player David Ortiz (Dominican)
Pierce Brosnan (Irish)
Alanis Morissette (Canadian)
Dave Matthews (South African)

Copyright 2009 by NBC Universal, Inc. All rights reserved.
This material may not be published, broadcast, rewritten or redistributed.

Keep your Access to everything in Hollywood! Breaking news and personal commentary from Nancy, Billy, Tony, Shaun, Maria & all of our producers! Follow us on Facebook and Twitter now!