During an interview with fellow American Idol alum Kelly Clarkson, Katharine couldn't help but gush over her and David Foster's newborn baby boy Rennie. "I'm a little bit tired here and there but I find time to nap and he's such a good little baby and I'm so in love," Katharine, who gave birth in February, said on The Kelly Clarkson Show. "I mean, you're a mom. It's my greatest job I'll ever have."
The 38-year-old host—who shares kids River Rose, 6, and Remington, 4, with ex Brandon Blackstock—agreed, however, she did point out one major detail. "I know it's so cliché, but it will be the hardest," Kelly told Katharine. "The hardest thing for me is when they're so freaking cute and you love them so much but they're doing something that's naughty. And you're like, 'Nope! You will not twist me around your finger.'"
Katharine, 37, noted that her friend also pointed out a similar scenario. "She was like, 'Oh, can you even imagine that you're gonna have to get mad at him one day?'" the Scorpion actress recalled. "I'm like, 'No! He's so sweet right now, I can't imagine.'"
However, Kelly assured her the day will come. "Trust me, it will happen," Kelly said. "It will happen and you'll go, 'Whose child are you?'"
In March, one month after welcoming her first child, Katharine revealed her son's name. "OK, well, his name, we haven't said anything, my husband hopefully won't kill me for saying it, but his name is Rennie David Foster," she said on Today With Hoda and Jenna. "We picked Rennie because I had actually been in labor for a while, we didn't have a name picked out."
She also shared that her music producer husband was on a text chain with his sisters, one of who suggested an "old family name."
"It was his great-grandfather's name, his great-uncle's name," Katherine explained, "so it has a long history in his family. My husband said, 'Hi, Ren Foster,' and so we said, 'That's a good name. It's a strong name.'"