Former "American Idol" winner Kelly Clarkson returns to the world of singing competitions on Thursday night in ABC's "Duets," and is revealing to "Extra" how she slimmed down just in time for the debut.When asked about her fitness secret weapon, the "What Doesn't Kill You Makes You Stronger" singer said, "I call her Chuck Nora. She's my trainer. I stole her from my boyfriend. She came off cool and not like a trainer. A lot of things are scheduled for me… she makes it fun, we go hiking."
She added, "Her name's Nora, but I call her Chuck Nora because she is like G.I. Jane… hardcore."
When asked about the nature of the competition of "Duets," Clarkson said, "I love competition and I think it's healthy. I think nowadays there is not a lot of talent development because the industry is finicky. I think it's cool for people to be able to find their feet on this show."
Kelly is joined in "Duets" by singing stars Robin Thicke, John Legend and Sugarland's Jennifer Nettles. John Legend tells "Extra," "We are not just judging, we're not just mentoring the artists… so that puts a whole other level of skin in the game for us."
Watch the season premiere of "Duets," Thursday at 8PM on ABC.