Comrie, 29, popped the question last weekend while the pair were "vacationing in Hawaii," Duff's rep said. "After having been together for over two years, they are very excited to share this happy news. They are thankful for all of your warm wishes."
Duff, 22, who previously dated Joel Madden — who just announced his engagement to Nicole Richie — told Us, "[Comrie's] a great guy. I've never met anyone who could say a bad word about him. He's generous, caring, funny. We just laugh our heads off, which I need in my life. ... He's unique. I wouldn't want to be with someone who wasn't unique."
Duff also told the magazine they have a surprisingly "natural" relationship.
"We both have busy jobs and we're both very focused people, so that helps," she said. "Since we are apart so much, it's not like one person is at home waiting for the other."
According to People.com, Duff, who has said she read "Hockey for Dummies" to better understand her beau, has become a fixture at his games. She also cheered him on when Comrie played for the Ottawa Senators, where she was joined in the stands by Carrie Underwood, whose fiancé Mike Fisher is on the team.
Comrie told Us, "We have fun. We both live such different lives, but it's always fun to support each other and spend time when we get to."