The X Factor judge, 53, is expecting a baby with New York socialite Lauren Silverman, 36, who's married to Cowell's friend, real estate mogul Andrew Silverman, Us Weekly reports. The Silvermans are in the process of divorcing.
"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 told Us. "As their marriage deteriorated, she and Simon became close."
An email to Cowell's rep was not immediately returned.