Kelly Clarkson on Brandon Blackstock romance: It's killing creativity

Kelly Clarkson has joked that her romance with boyfriend Brandon Blackstock is taking its toll on her creativity.

The 'Dark Side' singer has been dating Blackstock - the son of her long-time manager and step-son of Reba McEntire - since late 2011 but only publicly revealed the relationship in March 2012.

Kelly Clarkson performs at her London fan gig

Clarkson said that she has been attempting to write new music but finds herself gravitating towards lyrics which gush over her new love.

"It is killing me. I'm trying to write a tough song and it is coming out like butterflies and rainbows," the 29-year-old explained to People.

"It is ruining my creativity. I'm writing all this happy [stuff]. People are going to be, like, 'What the hell happened to you?' It has been really difficult. I love it. It's an awesome problem to have."

Clarkson, who has previously insisted that she has was happy being single, added that her partnership with Blackstock fits perfectly into her schedule.

"People used to ask, 'Why are you single?' and I'd say, 'It is not in my schedule'," she said. "I'm in a relationship right now and I have time for it. I never used to."

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Watch Kelly Clarkson's video for 'Stronger' below: