The X Factor judge and dad-to-be and his New York socialite gal (who's still technically married to her real estate mogul husband Andrew Silverman) are about 10 weeks pregnant together. The 53-year-old music exec and Silverman reportedly "became close" as her marriage "deteriorated."
While we waiting for baby Cowell to arrive, let's take a look past at Cowell's other women and past romantic relationships.
1976: At the age of 17, Cowell dated English model Paula Hamilton, who was 15 at the time.
1970s: Cowell still remains friends with his '70s girlfriend Jackie St. Claire.
1995: Cowell reportedly proposed to model Louise Payne, shortly after the two met. Their relationship fizzled just a few years later.
November 2007: It was rumored that Cowell was dating his fellow X Factor U.K. judge Dannii Minogue (Kylie Minogue's sister) when they were pictured together in a car holding hands after a benefit event in London.
2002-September 2008: Cowell and his longtime TV personality girlfriend Terri Seymour broke up after six years of dating. The couple met in 2002 when she interviewed him for a TV show.
2008: Cowell admitted to having an affair with Dannii Minogue in a 2012 interview. "I had a crush on her. It was Dannii's hair, the sexy clothes, and the t--s," he reportedly said. "I was like a schoolboy. She was foxy. She was a real man's girl. Very feminine. It was genuine love." The twosome allegedly got together right after his split from Seymour. It was also rumored that Cowell pursued his X Factor mate Cheryl Cole during their time on the show together.
July 25, 2013: Just a few days before his baby news broke, Cowell was snapped with a mystery woman sitting on his lap as the two left London restaurant River Café. The duo seemed quite cozy while driving off together.