Kelly Clarkson has praised Gwen Stefani as an "awesome girl".

Kelly Clarkson

Kelly Clarkson

The 35-year-old singer is set to star on the US talent competition 'The Voice' in her judging debut when season 14 kicks off next year, and she has admitted she's already become close friends with fellow judge and 'Hollaback Girl' hitmaker Gwen, as the pair have enjoyed a "magnificent" double date with their other halves.

Kelly - who is married to Brandon Blackstock, with whom she has three-year-old daughter River, and 19-month-old son Remington - said: "You know, we've already [double dated] at her house, which is magnificent. And her family was there. It's a real testament of how she's such an awesome girl - it's because of her family. Her family was super rad and down to earth. They're really, really cool."

The 'Piece By Piece' singer couldn't believe how "insane" Gwen's home was, and she couldn't help but feel out of place in the abode.

She added to E! News: "Her house is insane. I walked in and I literally felt like the 'Pretty Woman' scene when you don't belong in the store. I was like, 'I have a nice house,' but [with] hers, I was like, 'Damn!'"

It isn't the first time Kelly has gushed about spending time with 48-year-old Gwen and her boyfriend Blake Shelton, who also has a spot on 'The Voice' judging panel.

She said previously: "Recently we did get to hang at Gwen's house, which is insanely gorgeous. It was really cool. Brandon, Blake and I, we're all southern. Gwen's a southern Cali girl, yes, but I just mean ... we're all different. I think the common denominator is that we're all very chill, we love what we do, we're just kinda all normal kids. It sounds really funny."

But Kelly wasn't so calm when she first met Gwen, as she couldn't believe she was hanging out with the former No Doubt musician, who she grew up listening to.

She added: "And God, I grew up listening to Gwen, from No Doubt days. So, it's just really cool. She's really sweet and down-to-earth. And [Blake's] sweet and down-to-earth, my husband's like that. We're all just kinda very chill."