Katharine McPhee Reveals Origin of Her Newborn Son's Unique Name

The 'American Idol' alum and husband, David Foster, shared their baby boy's unique name in an interview on 'Today With Hoda and Jenna.'

Katharine McPhee is sharing the special meaning behind her and David Foster's son's name. In an interview airing Friday on Today With Hoda and Jenna, the Smash star revealed that the couple chose an "old family 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 told Hoda Kotb and Jenna Bush Hager during the virtual chat. "We picked Rennie because I had actually been in labor for a while, we didn't have a name picked out."

McPhee shared that Foster's sisters actually suggested the name, which holds sentimental value for the music producer.

"It was his great-grandfather's name, his great-uncle's name," she 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.'"

Earlier this month, the 36-year-old actress shared the first photos of their baby boy after giving birth in February. She gushed about how much she loved being a mom in the photo she posted to her Instagram Story.

Instagram/Katharine McPhee

"Just in case you were wondering...I love being a mommy!" she wrote alongside the photo of Rennie snuggled up to mom in a sling wrap.

ET recently spoke with the performer about her new Netflix series, Country Comfort, when she said she and Foster were feeling great amid her pregnancy.

"I am a little short of breath here and there," she shared. "Yeah, I mean, some days it's a walk in the park and other days it's like, oh gosh, OK! But, I feel really good. I'm in a good place."

She also revealed how her time on set with her younger co-stars got her even more excited for motherhood. 

"Being on set with these kids every day on the show... seeing the different stages of their life is just something to look forward to," she said. "There's always going to be a different stage to look forward to as a new mom."

While this is her first child, 71-year-old Foster has five daughters -- 34-year-old Jordan, 38-year-old Erin, 40-year-old Sara, 47-year-old Amy and 50-year-old Allison -- from previous relationships.