Kelly Clarkson has a lot of love and appreciation for her friend and fellow musician Carrie Underwood.
ET's Lauren Zima caught up with Clarkson backstage at the 2018 iHeartRadio Music Festival at the T-Mobile Arena in Las Vegas on Saturday, and she opened up about watching Underwood -- who is pregnant with her and husband Mike Fisher's second child -- perform at the festival.
"Carrie's killing it, and she's pregnant! What?!" Clarkson exclaimed. "I hated singing pregnant."
As for Underwood's pregnancy journey, Clarkson said she was overjoyed at the "Cry Pretty" singer's emotional experience.
"I'm so happy for her!" the Voice coach shared. "I didn't know a lot of the situations that were happening behind the scenes."
Earlier this month, Underwood sat down for an interview with CBS Sunday Morning, where she revealed that she'd suffered three miscarriages in less than two years.
"I have a lot of friends who have gone through that several times as well," Clarkson shared.
"It's a really cool thing [she did]. I was emailing her, because I was like, 'It's so important that you talk about it,'" she continued. "I know you don't have to, because it's a hard thing to do, but it makes women who feel inferior, or feel like something's wrong with them, it makes them feel comfortable, and [know] that people go through it."
Clarkson also said she'd love to have Underwood join her on her new talk show when it premieres next year on NBC.
The recently announced Kelly Clarkson Show, which is produced by the singer and her husband, Brandon Blackstock, will likely also feature appearances from the couple's adorable children as well.
"We have four, so I'm sure one of them will pop up every now and then," Clarkson joked, referring to the couple's 4-year-old daughter, River Rose, and 2-year-old son, Remington, as well as Blackstock's daughter Savannah and son Seth, from a previous marriage.
For more on Underwood's powerful, emotional pregnancy journey, watch the video below.
Carrie Underwood Breaks Down in Tears as She Receives Star on Hollywood Walk of Fame
How Carrie Underwood Got Through the 'Most Challenging Year' of Her Life (Exclusive)
Inside Kelly Clarkson's Upcoming Daytime Talk Show (Exclusive)