Simon Cowell has changed a lot of lives on American Idol, The X Factor, and Britain's Got Talent -- but he's about to undergo the most life-changing experience of all: fatherhood. The notoriously prickly Brit, 53, is expecting a baby with New York socialite Lauren Silverman, multiple sources reveal exclusively in the new issue of Us Weekly. "She's around 10 weeks along," the insider shares. And that's only part of the story. Silverman, 36, is technically still married -- to Cowell's close friend Andrew Silverman, a real estate mogul in NYC. She plans to leave her estranged husband to be with the father of her child. "Lauren and Andrew have been unhappy in their marriage for some time, and their divorce has been in the works for a while," a source tells Us. "As their marriage deteriorated, she and Simon became close." In any case, diaper duty is a big deal for the X Factor judge, who has said on more than one occasion in the past that he's not cut out to be a dad. "God, no. I couldn't have children. If I had them here drawing on the walls I'd go nuts," he crowed in 2009. "With kids, you've got a routine you can't escape from. You've got to be up at a certain time. Got to listen. When all you want to do is sit in a corner thinking." In recent years, however, his stance on the issue seems to have softened. Last year, he hinted in an interview with AOL Music that he hadn't entirely ruled out the idea of someday becoming a father. "Well...yes," he said when asked if he'd changed his mind about children. "And no. I do really, really like kids, because I can talk to them and listen to them. The problem has always been how much time you need to devote to bringing up kids. I've always dedicated all my life to work, and at 52, I've probably missed the opportunity." Cowell's reps were unavailable for comment.