The new panellist said that she admires her co-star's commitment to his wife and children.
Scherzinger told The Sun: "Gary is brilliant. I didn't really know him before. I think I really liked him the day I found out he won 'Celebrity Dad of the Year'.
"The pride he takes in his family and children - he's a true gentleman. He's a lovely, honest human.
"And he's a great dad. All he does is talk about his family. I love that."
However, Scherzinger admitted that she was stunned by Barlow's popularity when she first joined the panel.
She told: "I thought I was something special until I came on the show. I thought the fans were waving at me but they just knocked me aside to take pictures of Gary.
"I was like, 'Really? That's what's happening now? All right, I'll take the picture of you with Gary'."
Scherzinger added: "He's just a grade A human. It kind of sucks. He puts us all to shame.
"He's going to be knighted. It just sounds right - Sir Gary Barlow."
The former Pussycat Doll, who is dating Formula 1 driver Lewis Hamilton, also revealed that she would love to have a family of her own.
"I definitely want kids. I come from a big family. Family is so important to me. It's everything." she said.