Dax Shepard and Ashley Olsen secretly dated, he was 'thunderstruck' by 'her beauty'

Who knew that Dax Shepard and Ashley Olsen used to date? The Parenthood actor made the revelation about his private life on Monday's Armchair Expert podcast.

"So, I dated Ashley Olsen and she's just the most wonderful person. She's fantastic," he exclaimed.

Shepard brought up the secret romance when his co-host, Monica Padman, was talking about how much she loves Mary-Kate and Ashley's clothing line The Row. Shepard said he dated Olsen around the time she and her sister were getting it off the ground.

“When we were dating, it was when she was kind of putting all her energy and focus into launching that in a big way. So, I was able to see her meet with design teams and, like, run her s*** and she handled her [business], and it's very impressive," Shepard added.

Shepard, 47, and Olsen, 35, dated "about" 15 years ago with the podcast host admitting they seem 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."

Although Shepard called his ex a "major f***ing" boss, he never watched Full House.

"I luckily never saw that show because I probably would have not been able to be attracted to Ashley if I knew her as a baby," he quipped. "I just saw her at a party and was kind of thunderstruck with her beauty."

Olsen and Shepard's romance fizzled out just as quietly. He went on to marry Kristen Bell, whom he met in 2007. Bell and Shepard share two young kids. Olsen still keeps her private life very much under the radar. She was most recently linked to artist Louis Eisner.