"She loves the Jonas Brothers," Kaley exclusively told E! News in an interview alongside costar Chris Messina. "She's obsessed."
And when it comes to expanding her taste in music, the infant really isn't burnin' up for any other artist right now–although Kaley noted that Matilda does love "Twinkle Twinkle Little Star."
The 37-year-old joked, "So if Jonas Brothers could record a 'Twinkle Twinkle Little Star' that would be really great for our household."
As to how Matilda discovered the brothers?
"We turned it on, and I thought it was a fluke, and she was listening," the Flight Attendant star explained, "and then the next night I put it on in the bathroom when she was crying, and again she looked up and was listening."
"I was like 'oh, it's not a fluke.' She loves them," Kaley continued, jokingly adding, "So this is her first crush, on the Jonas Brothers."
And while Kaley and Tom welcomed their daughter in March, Matilda was along for the ride with the Big Bang Theory star's new series, in which she and Chris play a true crime-obsessed couple who get in over their heads when they try to catch a killer.
Kaley was working on the new series up until three weeks before she gave birth, but as it turns out, the biggest side effect was actually felt by Kaley's costars, including Tom Bateman, Liana Liberato, Priscilla Quintana and Natalia Dyer in addition to Chris. They had to eat whatever food Kaley was currently craving.
"Taco Bell, Del Taco, donuts—it was disturbing," she told E! News. "Everyone had to get trainers when we got off the show. They were all mad at me, I had to pay for all their trainers and gym memberships."
"The weirdest craving I had the whole time was ice," she admitted. "Everyone would bring me ice, and I would chomp it."
Chris had his own thoughts about this particular habit. "Yeah there was a lot of chomping," he added, while Kaley laughed. "A lot of annoying chomping."
Based On A True Story premieres June 8th on Peacock.
(E! and Peacock are both part of the NBCUniversal Family.)