Kelly, who also joins Louis Walsh and N-Dubz singer Tulisa Contostavlos on the panel of the talent competition, has taken a special liking to the Take That star.
The 30-year-old said: 'I can hardly talk to Gary without blushing.
'He is so handsome and so charming. But I know he's married - I've met his wife and she is lovely. And girl, she has a nice piece of husband at home!'
And it's not just Barlow, 40, who is the object of the Kelly's affections - she also likes 59-year-old Louis.
The former Destiny's Child star said: 'I love Louis. I love his little booty - it's so petite.
'When I hug him, I always slide my hands down to his butt.'
Talking seriously about her love life, Rowland said she decided to change things 'real quick' when she realised she was dating the wrong sort of men.
The singer, who has previously romanced rapper Nelly and got engaged to American footballer Roy Williams, added to British Grazia magazine: 'When I noticed myself starting to date a-hole guys, and unavailable guys, I changed that real quick.
'I definitely want to get married and I definitely want to have babies.'
All eyes are on this year's eagerly-anticipated new series of the UK X Factor, which kicks off this Saturday, but Kelly isn't bothered about competing with former judges Cheryl Cole and Dannii Minogue.
Speaking about the pressure she faces, she said: 'Oh, I'm not scared, I'm excited. I'm not intimidated. Not at all. I know Cheryl is the nation's sweetheart. But I'm not trying to be Cheryl, because Cheryl does Cheryl best. I'm not trying to be Dannii, because Dannii does Dannii best. I'm just going to be myself.'