David Foster & Katharine McPhee – 34 Years

The weirdest thing about David Foster’s marriage to Katharine McPhee isn’t even the 34 year age difference. No, sir, the really strange thing about their marriage is that McPhee is a year younger than Foster’s third daughter Erin. She even jokingly commented “Mommmyyy” on the couple’s social media engagement announcement.

Foster, of course, has been married before. This is, in fact, marriage number five. But he vowed that after some introspective thought when marriage number four ended, that his marriage to the Idols runner-up will be his last. They tied the knot in 2019, and Macphee birthed their first child in February 2021.