Simon Cowell once proclaimed, "I don't believe in marriage, certainly not in this business." But the 50-year-old American Idol judge and notorious cad is singing a different tune these days thanks to his new romance with the woman who has done his makeup behind the scenes on AI for years: Mezhgan Hussainy. The two are engaged, and now one of Simon's closest friends, recording artist Sinitta, is revealing how Mezhgan came out of nowhere to capture the playboy's heart.

"He's suddenly woken up and realized she's the person he wants to spend the rest of his life with," Sinitta tells Life & Style exclusively. "She's fun, very easy to be with. I'm not surprised they got together."

Mezhgan, 36, has been doing makeup for AI since season two, in 2003. "She's very grounded and has clearly made him very happy," Simon's pal and America's Got Talent judge Piers Morgan tells Life & Style. "Simon was always going to fall for a makeup artist -- that way he has someone permanently around to make him look perfect." All joking aside, season two contestant Kimberly Caldwell thinks Mezhgan's an ideal match for Simon too. "She's just down-to-earth, a cool chick. She and Simon started out as friends and have a strong comfort level with each other," Kimberly told Life & Style at the 11th Annual Children Uniting Nations Oscar party in LA on March 7.

For more on Simon and Mezhgan, pick up the latest issue of Life & Style, on newsstands now!

Photo Credit: Startraks