Katy Perry's blooming romance with former Canadian Prime Minister Justin Trudeau is heating up. "Katy is really into it. She's very happy," an inside source tells Us Weekly exclusively. "She's trying to keep it low-key, and they've spent a lot of private time together. She's not looking to publicize this relationship." The source adds, "Their friends think they are a good match, but he actually hasn't met a lot of her friends yet." Us has reached out to Perry's and Trudeau's reps for comment.