The Britain's Got Talent judge, who defected from the BBC ballroom reality show in January, believes that the ITV competition "has everything".
"I felt three years was a respectable amount of time," she told the Daily Star. "It was a fantastic experience as a contestant and as a judge, and it was time for new things.
"I don't want to be predictable. I want to try new things. I want new challenges. That's what life is all about."
The 33-year-old said of judging Talent: "This show has everything. Not only do I love dancing but I love singing, I love dancing dogs, I love comedy, I love everything entertainment.
"This is the one show that enables and encompasses all that."
The 'Knockdown' singer later insisted: "I'm not going to do anything different, I'm just going to be myself.
"You know me, I stand up for myself all the time. I don't like bitchiness and I don't like controversy and all that negative stuff.
"I can't pretend to be something that I'm not. All I can be is honest and myself. That's what I've always done."
Britain's Got Talent returns later in the spring on ITV1.
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