The 47-year-old made the confession in the Monday, February 28 episode of his "Armchair Expert" podcast. "So, I dated Ashley Olsen and she's just the most wonderful person. She's fantastic," he raved.
"When we were dating, it was when she was kind of putting all her energy and focus into launching that in a big way," Dax said of Ashley and Mary-Kate Olsen's clothing line, The Row. "So, I was able to see her meet with design teams and, like, run her s**t and she handled her [business], and it's very impressive."
Noting that he dated Ashley "about" 15 years ago, the podcaster admitted they were like an odd pairing. "They're sarcastic," he said of the Olsen twins. "I would imagine on the surface that's a pretty weird pairing but [Ashley's] super funny, and sarcastic, and intelligent."
Dax went on to reveal that he had never seen Ashley on "Full House". He explained, "I luckily never saw that show... Because I probably wouldn't have been able to be attracted to Ashley if I knew her as a baby. I just saw her at a party and was kind of thunderstruck by her beauty."
It remains unclear when Dax and Ashley called it quits. The "Hit and Run" leading man himself began dating Kristen Bell in 2007 before they tied the knot in 2013. The pair now share 8-year-old daughter Lincoln and 7-year-old daughter Delta.
Last February, Dax admitted that his marriage to Kristen has not always been "easy." Speaking to "Sunday Today" with Willie Geist, he said, "We don't want anyone to think we met and it's been easy because if that's someone's expectation of a relationship and certainly a marriage, it's a bad expectation to have."