Kelly Clarkson says it ''drove [her] nuts'' being forced to work with Dr. Luke.

The 35-year-old star was tied down to a seven-album deal with RCA after winning 'American Idol' in 2002, and she has admitted not being ''a fan'' of the music producer's ''character'' when she teamed up with him.

She said: ''I was just asked about his character - not a fan. I mean, that's obvious.

''What drove me nuts before with my label was like, I get it, the dude is talented, that's great. But there's like a plethora of other producers and songwriters out there that we can be working with.

''So that's what drove me nuts. Not having the choice or my record would get sat on.''

Luke - who was accused of sexual assault by Kesha, which he denied and a judge dismissed - co-wrote Kelly's huge hit 'Since U Been Gone', which made the top five in the UK and US Singles Charts.

The 'You Found Me' hitmaker - who has kids River, three, and 19-month-old Remington with husband Brandon Blackstock - also claimed her label tried to get her to compete with scantily-clad musicians when she was working on her second studio album 'Breakaway' in 2014.

Speaking on The Sun's Bizarre Life podcast, she added: ''I remember making the 'Breakaway' album. Someone came in and brought in some pictures, some chick naked with a guitar on the cover of a magazine.

''They were like, 'This is your competition'. I'm like, 'That ain't my competition. I can't compete with that'.''

Kelly admits the only time she could get a moment alone around the time of making 'Breakaway' was on a treadmill, but her hard exercise led to her picking up a knee injury.

She said: ''Any time you saw me thin, honest to God, the reason is 'cause I lived on a treadmill and I'd put my in-ears in so people would stop talking to me, 'cause I was so tired.

''Especially those 'Breakaway' days, I was tired. I was always surrounded by people, I never had a minute alone. So my minute alone was on a treadmill and I wrecked my meniscus 'cause of that.

''I'm a singer. We're not models. I don't see my life as a struggle. I just see me living my life.

''Sometimes you're thin, sometimes you're thicker. Sometimes you're happy, sometimes you aren't as happy.''