Kevin Jonas and his wife were forced to take their youngest daughter to physical therapy in a bid to get the baby on her feet.
The former Jonas Brothers star shares two girls with his wife Danielle Jonas, and reveals the couple became concerned when Valentina, who turns two in October (18), failed to take her first steps at the normal age, between nine and 12 months.
"We actually had to go to physical therapy with her," Kevin tells Us Weekly. "Then one day, she just stood up on her own and started walking! And now she's running."
Although Kevin and Danielle are pleased Valentina is now making significant progress, he admits they were worried her lack of walking indicated a more serious health issue.
"You want your kids to be developing at the right level and everyone says, 'They'll be fine, they'll get there,'" he shares, "but you get concerned. You just want to make sure there's nothing else."
After doing their due diligence, the proud parents are happy to report Valentina is OK.
"She's in great shape now!" dad Kevin gushes.
Meanwhile, the 30-year-old's eldest, Alena, is following in his musical footsteps, with Kevin admitting the four-year-old is "just me as a girl".
"She tells both of her uncles (musicians Joe and Nick Jonas) that she's going to go on stage first, then they can do their show," mum Danielle laughs.
And while there's no talk of a Jonas Brothers reunion, Kevin admits the entire family still enjoys jam sessions following the band's split in 2013.
"There are guitars everywhere around all of our houses. Pianos. Guitars. It's kind of just in our blood. It's in our nature," he explains. "It's not like we're trying to do anything special, it's just that we're hanging out and music is a part of who we are. It always happens."