SYDNEY (AFP) - British actress Miriam Margolyes, best known for her work in the Harry Potter films, became an Australian citizen on Saturday, saying she felt that the rest of her life would be "joyous".

Margolyes was one of 100 people taking the pledge at a ceremony in Canberra attended by Prime Minister Julia Gillard, and one of a record 17,059 people from 145 countries to become citizens on Australia Day.

"This is your new country, and you'll never want another," Gillard, who was born in Wales and who came to Australia as a small child, told the gathering. "Welcome to citizenship. Welcome to Australia. Welcome home." Margolyes, 71, who won the BAFTA for best supporting actress for the 1993 Martin Scorsese film "The Age of Innocence" and played Professor Sprout in two Harry Potter movies, joked it had taken her years to take the plunge. "Well, you have to be sure, don't you," she said. "Now I am. I'm just very happy to be here and I will be with friends and the rest of my life will be joyous."