Kelly Clarkson believes Christina Aguilera and Blake Shelton's voices "blended really well" on their new single.
Christina and Blake collaborated on Just A Fool, a song on the pop songstresses' upcoming album Lotus.
The pair served as co-mentors on US TV talent programme The Voice, but they have very different musical backgrounds.
Christina's vocals are more R&B oriented while Blake's is immersed in country.
Kelly was in awe of how beautifully the singers harmonised together on Just A Fool.
"Well my manager told me that, he's like 'Hey you, [Blake] did a duet with Christina?' " she recalled to MTV News.
"I love both of them. I was just curious how both of them would sound together.
"And he played it for me and it was really awesome. I cannot wait for everybody to hear it. I guess you just don't think they're two such different voices like, or distinguishable voices, they're just like very different. And then, but it came together nicely. They both blended together really well. It was awesome. It's really good."
Christina's new album Lotus will be released on Friday.
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