British-born actress Emily Blunt became a naturalized U.S. citizen in August, but she said one thing has made her question her decision--watching the Republican Presidential debate.

"I became an American citizen recently, and that night, we watched the Republican debate, and I thought, 'This was a terrible mistake. What have I done?'" she told the Hollywood Reporter while promoting the movie "Sicario" at the Toronto Film Festival.

Last week on "Jimmy Kimmel Live," Blunt expressed additional reservations.

"I'm not sure I'm entirely thrilled about it," she said. "People ask me about the whole day. They were like, 'Oh, it must have been so emotional.' I was like, 'It wasn't! It was sad!' I like being British."

The reaction on Twitter was overwhelmingly anti-Blunt.

Blunt, 32, went through the naturalization process with Matthew McConaughey's wife Camila Alves, and said the hardest part for her was pledging her non-allegiance to her former queen.

"It wasn't specifically Queen E, but she knows," she said. "The thing that's weird is I do get to keep both my British citizenship and this, but you have to renounce her. So, it's kind of typically American -- not to be rude -- but I had to renounce her in the room but I don't actually, technically renounce her. They were like, 'Just say it. You don't have to mean it, but just say it.'"

Blunt is married to American actor John Krasinski, best know for his role in "The Office."

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