Mischa Barton is to become a US citizen.The stunning 'O.C.' star, who was born in Britain but moved to New York as a toddler, has already taken her citizenship test and is now awaiting for the resultsMischa admits she was really worried about sitting the exam because she was told the questions were tough.She is quoted in Scotland's Daily Record newspaper as saying: "I was really nervous about it because they make it so difficult. But it was fine. There were questions like, 'What colours are in the American flag?'"Last week, Mischa was whisked away to Paris as a birthday treat by boyfriend Cisco Adler.The Whitestarr rocker took the sexy actress to the French capital as a surprise to celebrate her 20th birthday.Barton was doubly thrilled with the unexpected trip because the holiday coincided with Paris Fashion Week.

A source said: "She got to sit in the front show of the Christian Dior show.

"Cisco didn't know the trip would coincide with Paris Fashion Week, but it all worked out perfectly."

Tagged in