Jennifer Lopez’s ‘X Factor’ advice to Britney Spears, Demi Lovato

As Britney Spears and Demi Lovato prepare to take their new judges seats on “The X Factor,” a diva who’s gone before them, Jennifer Lopez, has offered advice.

“I was like, ‘Live TV! Eek.’ It’s a big thing to take on, but I think they’re both more than capable to handle it,” the “American Idol” judge told “Access Hollywood” Monday night after Fox execs finally made it official earlier in the day that both pop singers would join Simon Cowell and L.A. Reid in the talent search.

Making the jump from performer to mentor and critic was fun, she said at the “What to Expect When You’re Expecting” premiere. “Working with the singers and doing your thing and knowing what you’re talking about from experience, and they both have that,”

Another must-have for a judge, according to J. Lo: an understanding that nice guys can finish first.

“You don’t have to be tough. There’s not one way to do that, reality TV, and those competition shows [are] about being yourself. It’s about being your best self, and I think that’s the most important thing,” she said.

Next week, Lopez will complete her second stint as an “Idol” judge alongside Steven Tyler and Randy Jackson, then embark on a world tour with Enrique Iglesias starting in July.

RELATED:

Britney Spears is engaged to Jason Trawick

Paula Abdul caught in shakeup at Simon Cowell‘s ‘X Factor’

Britney Spears’ ‘Femme Fatale’ lures Lady Gaga to Atlantic City

Follow Matt Donnelly on Twitter @mattdonnelly.