Although she was born and raised in Britain, and although she is most associated with a British role in a series produced by a Canadian company that aired on Showtime in the U.S., Gabrielle Anwar is very much an American actress, thanks to her roles in American movies and TV shows. (She's also an American citizen.)
Gabrielle Anwar is well known for her role as Princess Margaret Tudor in "The Tudors," the aforementioned series that aired on Showtime, about the House of Tudor that ruled England from 1485 to 1603. (The series actually ended with the death of King Henry VIII in 1547.) But for six years (2007 to 2013), she also played Irish Republican Army operative turned freelance commando Fiona Glenanne in the USA series "Burn Notice." She first came to the attention of American audiences at 22 in the 1992 movie Scent of a Woman, as Donna, a girl who dances the tango with a retired, blind Army officer played by Al Pacino.
Fun fact: One of Gabrielle Anwar's earliest roles was in a Paul McCartney video - specifically, his promotional video for his 1986 single "Pretty Little Head." She was sixteen years old at the time.