While the 26-year-old actress and singer says she hasn't met her former step-father's baby girl yet, she has seen pics of Ashton and Mila's 1-month-old child.
"I reached out to him when he had the baby, which is so awesome," Rumer said during a recent appearance on Access Hollywood Live. "I saw photos of her [Wyatt]. She's very cute."
But don't count on Rumer signing up for babysitting duty anytime soon. Rumer says between little Wyatt and dad Bruce Willis' two daughters Mabel and Evelyn, there aren't enough hours in the week to visit them all. "I have so many babies to babysit. I don't know if I have time!" Demi Moore's daughter joked.
Wyatt aside, Rumer reflected on Ashton's relationship with her mom (Ashton and Demi started dating in 2003 when he was 25 and she was 40. They divorced in 2013).
"I realized the other day, that he was a year younger than me when he and my mom started going out. That would be like me meeting someone who already had three teenage kids, kind of going into that situation was crazy," she dished.
"My mom has always made how [my sisters and I] feel about situations the most important thing," she added of the situation. "I think it was more her going, 'Hey, this is my life and these are my kids and my priorities. So if you want to come and kind of join our crazy clan, this is what I already have kind of built.' Which I find so amazing and respectful. It's one of the things that I admire most about my parents, is that they set such an incredible example for kind of putting their children first and keeping a family together, no matter what."