"He's just the sweetest man I know," Alison Brie says of her new fiancé, Dave Franco
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Alison Brie may be playing a serial cheater in the new comedy Sleeping with Other People, but off-screen she is happily engaged to actor Dave Franco. “I have an incredible fiancé,” Brie tells PEOPLE in this week’s issue. “He’s so wonderful. He’s just the sweetest man I know. And he’s so funny and incredible in every way.”

The actress, 32, says costarring with Jason Sudeikis in the film was also a lesson in hilarity. “He makes me laugh so much. We had the best time shooting this movie together. It was just like a blast,” Brie adds. “I think I kind of thought that we would get along and then I was excited that we actually did. We have some friends in common so it felt like we should have met ages ago.”

Franco, 30, proposed to Brie in August with a rose gold diamond ring designed by Southern California jewelry designer Irene Neuwirth. His brother James Franco Instagrammed a photo of the couple with the caption: “Congrats Davy and Allison!!! engaged!!! I WUUUUUV YOU.”

The couple, who have reportedly been dating since 2012, call L.A. home for now but the actress says she loves New York, where the film shot. “I’m here right now and today when I was walking around I was just like, ‘This is my favorite city. I love being here, I love this place,’ ” Brie says. “Every time it’s not long enough. I’m already like, ‘I should get a place here.’ ”

For more of Alison Brie’s interview, pick up this week’s issue of PEOPLE, on newsstands Friday