Chris O’Donnell was on set at “NCIS: Los Angeles,” checking his emails, when co-star LL Cool J started looking over his shoulder. O’Donnell happened to be reading about a reality TV idea that his buddy Reinout Oerlemans had just pitched.

The concept is what would become “Come Dance With Me,” a new family-oriented dance competition that premieres April 15 on CBS. But at that moment, O’Donnell wasn’t quite sure he was up for working on a competition show.

“[LL] says, ‘What are you looking at?’” O’Donnell recalled. “I told him it was my friend’s idea for a new show. He goes, ‘I think that thing’s hot! You should do it. This is up your alley.’ And then he was like, ‘I’ll do it if you do it!’”

O’Donnell replied to Oerlemans: “So good news, not only will I do it, but my buddy Todd will do it too!”

That’s the quick explainer on how the two stars of “NCIS: LA” wound up partnering with 3 Ball Productions to create “Come Dance With Me,” which follows talented young dancers who partner with an untrained family member to perform together and compete for a prize.

Teams will learn different dance routines, including hip hop, ballroom, contemporary and theatrical, and receive scores from the judges that determine whether they’ll continue. Each episode ends with the two lowest-scoring teams in a freestyle dance-off, with one of those two groups eliminated. Parents partnering with their dance kids include a preschool teacher, a doctor, a social worker, an engineer… and the drummer for Limp Bizkit.

“I liked the idea of families getting together and the music,” LL Cool J said. “This idea of kids getting with the parent, the adult in their life who’s meaningful to them, and going on a show and having their dreams come true — especially with what we’ve been going through over these past couple of years.”

O’Donnell noted that the rise of TikTok dance challenges, especially with families during COVID, is an advantage to next month’s “Come Dance With Me” launch.

“Watching my daughter teach my sons how to do these TikTok dances, things just kind of lined up to where the moment was right for something like this,” he said. “And when you bring in the emotional element of these kids, who are all trained dancers, bringing in someone in their life with a meaningful relationship, who may not be experienced, it’s not just about the dancing. It’s more about the personal journey that these people have been on.”

“Come Dance With Me” adds another layer of a partnership between LL Cool J and O’Donnell that has now spanned 13 years — back to the launch of “NCIS: Los Angeles” in 2009.

“Every day, even though there are directors and people around, he and I always have a separate conversation between the two of us that only the two of us are privy to,” O’Donnell said. “Whether it be about the actual scene we’re working on, or stuff that’s coming down the pike or our careers in general and personal life. I feel like we’ve been in production on our lives for the past 13 years. And this is just another big conversation topic that we’re going through. There’s a shorthand that has evolved over 13 years and a trust, which goes a long way.”

LL Cool J isn’t a stranger to reality competitions, having hosted “Lip Sync Battle.” And O’Donnell is a fan of dancing competitions dating back to 1980s syndicated classic “Dance Fever.”

“I grew up on it,” he said. “It was like, 5:30 on Saturday nights. You’d come home and Deney Terrio would be on.” O’Donnell said he admired how the show’s judges would still find a way to compliment poor dancers before giving them a low score: “They’d say, ‘I wish I had that much confidence when I dance. And I love your costumes.’ And then give them a 58. It was great.”

Grammy-winning songwriter Philip Lawrence hosts “Come Dance with Me,” which features judges including dancer/actor Jenna Dewan, dancer Dexter Mayfield and hip-hop choreographer Tricia Miranda. LL Cool J and O’Donnell will stay behind the scenes for Season 1.

“Honestly, it’s not always about us in front of the camera,” LL Cool J said. “I think it’s cool to just create something and put something out there for people to enjoy. I don’t always have to be in front of the camera for it to be successful or for it to be meaningful to me. So I’m good with a background role in this one.”

It also was a logistical issue: Don’t forget, LL Cool J and O’Donnell still have their “NCIS: LA” day jobs. “We weren’t able to go even if we wanted to be on camera, because of all the quarantines,” O’Donnell said. “If the show continues to go and the audience receives it, maybe you’ll see us at some point. But for right now, we’re excited about what we’ve done. And looking forward to audiences getting to take a peek at it. We all know what a crapshoot these things are. The best intentions, the best product, that doesn’t always mean eyeballs are going to tune in. We both have been around the block long enough to realize that, and when something works, it’s very fortunate. We feel like we’ve put out a good product, we hope people tune in, I think families are going to really enjoy it.”

O’Donnell and LL Cool J are creators and executive producers of “Come Dance with Me,” along with 3 Ball Productions, part of 3BMG, in association with CBS Studios. Oerlemans, Ross Weintraub and Jeff Altrock are EPs for 3 Ball; Jeff Thacker, Nick Florez and RJ Durell also are executive producers.

But just because they’re now reality dancing TV producers doesn’t mean LL Cool J or O’Donnell have any plans to try out their stuff on “Dancing With the Stars.”

“My moves are pretty limited,” said O’Donnell. “I think I peaked in about eighth grade.” Added LL Cool J: “That might not go right for me. That could be a bad look for me, if I don’t have a mic in my hand, and I’m not rapping a song. I don’t know if you want to see me on ‘Dancing With the Stars.’ But you never know, right?”