She recalls of the “profound feeling” of becoming an American citizen, “It brought up feelings of patriotism that I didn’t think I had”

Helen Mirren is a dame – but she’s also a proud American. The 76-year-old British Oscar winner, who was appointed a dame by Queen Elizabeth II in 2003, became an American citizen in 2017, something she takes enormous pride in. “My husband [Taylor Hackford] is American. My stepchildren are obviously American. My nephew lived in America, worked in America,” she tells PEOPLE in this week’s issue. “So I had certainly been an American resident for a very long time.” The actress adds, “When I understood, which I hadn’t quite grasped before, that I could be a British citizen and an American citizen — because I would not like to give up my British citizenship — then I thought, ‘Well, that’s great. That’s the perfect world.’ ”

Mirren says it was “so moving” when she got her American citizenship. “I didn’t realize how profound a feeling it would be,” she recalls. “It brought up feelings of patriotism that I didn’t think I had. I think it was to do with the intrinsic generosity of America.” The Good Liar actress was living in New York City during the terrorist attacks of 9/11, performing in a play at the time. “I saw the second tower come down,” she says, looking back. “I had an epiphany. I realized where my allegiance and my heart and my intellect lay in that confrontation between extremism, religiosity — all those things and everything that America represents.” “And I thought, ‘I’m an American,’ ” Mirren adds. “I got an American flag, and I put it outside my window.”

Mirren is soon to be honored with the Life Achievement Award by the Screen Actors Guild on Feb. 27. “It’s a pinnacle,” Mirren tells PEOPLE. “From a pinnacle, you’ve only got two choices and that’s down or up to the clouds. Having said that, it’s a great pinnacle to find yourself standing on.” To date, Mirren is the most decorated SAG Life Achievement recipient, with a total of 13 SAG Awards nominations and five SAG Awards acting wins.

The 28th annual SAG Awards will be simulcast live on TNT and TBS on Sunday, Feb. 27, 2022, at 8 p.m. ET/5 p.m. PT from The Barker Hangar in Santa Monica, California.