‘X Factor’ Tension: Simon Cowell Tells Demi Lovato To Sit In ‘Naughty Chair’ (EXCLUSIVE DETAILS)

By: Dylan Howard / May 24, 2012

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Demi Lovato has done more than ease into the vacated X Factor judge’s chair — she’s also assumed Nicole Scherzinger‘s role as head honcho Simon Cowell‘s chief antagonist.

The 19-year-old’s first day of judging the hit Fox show in Austin, Texas, involved a day of put downs – not just reserved for contestants. She put Cowell, 52, in his place too.

A source at the auditions told Celebuzz: “Demi has really been brave with Simon, constantly reminding him how young she is and how old he is.

“At one point she told the audience, ‘He’s just old and impatient.'”

Later, Cowell was joking about a contestant butchering one of Lovato’s own songs to which the “Skyscraper” songstress snapped back: “At least I have a song Simon!”

Cowell responded, “Demi, I think you need to sit in the naughty chair for a few minutes today.”

The source told Celebuzz that it was nothing more than “playful banter” and “Simon thinks Demi is hilarious.”

It wasn’t their first only of the day. As Celebuzz reported, Lovato called out her boss for being over the hill.

“Within a few minutes of judging starting, Demi called Simon ‘grandpa’ because he’s seemingly decided to play the role of Cupid for her,” someone in the audience told Celebuzz.

Meanwhile, Lovato’s fellow new judge Britney Spears took to Twitter on Thursday to dispel reports that she walked off stage during the middle of the auditions after a budding contestant did a rendition of her hit song, “Hold It Against Me.”

Spears, 30, wrote: “#Britneywalksoff??? LOL was just taking a little break people. I am having the BEST time!!!”