In a new interview with Howard Stern on his Sirius XM channel, the 26-year-old Dancing with the Stars contestant admits Ashton and Demi's May-December romance was awkward given that the former That '70s Show actor was one of her celeb crushes when she was younger.
"He was one of many on the wall, but I totally did," she says about hanging his poster in her bedroom. "I feel like I told my sister that, 'Man, ugh, alright, gotta cross him off the list.'"
But she says the awkwardness didn't last very long, and she quickly accepted his role as stepfather.
"It was definitely weird for a minute but I have to commend him, he was a really great stepfather and the perspective shifted very quickly," she shares. "That's when you open up your Teen Beat and then you just take him down, find someone else and put him up."
Ashton, 37, and Demi, 52, were married in September 2005, but separated in 2011 following an Us Weekly report that Ashton cheated on Demi with a woman named Sara Leal in San Diego. Looking back, Rumer says she didn't feel any skepticism about the relationship despite plenty of naysayers given the former couple's age difference.
"I feel like I was kinda impressed," Rumer laughs, referring to her mother. "I was like, 'Yeah girl, get it, alright.'"
Earlier this month, The Longest Ride actor Scott Eastwood dropped a bombshell during his Watch What Happens Live appearance, when he claimed that he was actually dating Sara Leal when she allegedly cheated on him with Ashton!
"He did sleep with one of my ex-girlfriends -- but she was my current girlfriend at the time," he said. "Well, I think it was the catalyst that broke him and Demi up."