Emily Blunt was "sad" to give up her British citizenship and become an American earlier this summer (15).

The actress, who is married to John Krasinski, has been an American citizen for a month and she admits she's still getting used to it.

She explains, "I'm not sure I'm entirely thrilled about it. People ask me about the whole day, they're like, 'Oh, it must have been so emotional...' and I was like, 'It wasn't. It was sad. I liked being British'. It was the most bizarre day."

And the surreal day got even stranger when Blunt realized she was being sworn in as a U.S. citizen alongside Matthew McConaughey's Brazilian-born wife, Camila Alves.

She adds, "McConaughey shows up looking like he's going on safari. I was like, 'You could have worn a shirt and tie! Camila looks amazing'.

"John (Krasinski) was there. I said, 'John did you enjoy the whole ceremony?' and he said, 'I did. I was doing the best I could not to stand next to McConaughey in that courtroom and say, 'All rise, all rise, all rise!'"

McConaughey is famous for his laid back catchphrase 'All right, all right, all right'.

Blunt tripped up when she appeared on pal Jimmy Kimmel's late night chat show in America on Tuesday (08Sep15) by failing to answer his simple questions about U.S. culture.

The actress couldn't figure out the initials 'MLB' stands for Major League Baseball and she had no idea 'DQ' is short for popular ice-cream chain Dairy Queen.