The 57-year-old actor is a British national, who had applied for the citizenship after Brexit last year, reported FemaleFirst.
Firth is married to Italian film producer Livia Giuggioli since 1997 and the couple have two sons, Luca, 16, and Matteo, 14.
Expressing his happiness about his request being granted, the Oscar-winning actor said, "A connection with Italy has existed in my family for more than two decades now. I was married there and had two children born in Rome. My wife and I are both extremely proud of our own countries. We feel that we've made a gift of that to each other.
Firth said that his wife is applying for a British passport. He said it will be "a huge privilege" for him to join Livia and his children in being dual citizens.
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The "Kingsman: The Golden Circle" star however, added that he "will always be extremely British (you only have to look at or listen to me). Britain is our home and we love it here."
In 2016, Firth had described the UK's vote to leave the European Union as "a disaster".
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