Jennifer Lopez's 'American Idol' Past: A Look Back

J.Lo first surfaced on season six as a mentor, drawing on her dance roots to motivate 'Idol' wannabes.

When Jennifer Lopez appeared on "American Idol" in 2007 and pronounced her love for the infamous Sanjaya Malakar, who could have predicted that the diva-turned-guest mentor would one day return to the reality competition?

But return she has, this time as a judge. As we prepare for her debut Wednesday night (January 19), alongside Randy Jackson and Steven Tyler, we're taking a look back at J.Lo's season-six "Idol" appearance, looking for clues as to how she'll handle the tricky task of being both entertaining and instructive in the course of a seconds-long sound bite.

Lopez stepped into "Idol" world for Latin night, when there were eight contestants still vying for the crown. What shines through most during her rehearsals with the singers is her desire to be supportive. When Haley Scarnato struggled to inject some passion into her performance, Lopez invited beat-boxing impresario Blake Lewis into the room to provide some energy. And instead of slamming Phil Stacey for butchering Santana's "Maria Maria," she urged him to imagine singing to someone as a way to connect with the emotional core of the tune.

"The songs have to mean something," Lopez explained. "They have to come from somewhere. Otherwise you just leave people feeling vacant."

That's a key insight, even if it's a bit obvious, and it'll bear repeating again and again as the new contestants move onto increasingly bigger stages as the competition progresses. But it's not just compassion and assistance with vocals that Lopez provided to the season-six crew. She also drew on her years as a dancer to help with the contestants' theatricality.

"Ride the rhythm," she told LaKisha Jones as the two shimmied side by side. J.Lo also hoped that eventual winner Jordin Sparks would infuse her performances with more hip-shaking mojo, saying, "Let the rhythm in her body just move her a little bit."

Mentoring contestants for one day, of course, is a very different task than judging them for an entire season. It remains to be seen if Lopez will channel her '07 performance during the new season, or whether she'll seek to stake out new territory or fill in perceived personality gaps left by the departures of Simon Cowell, Ellen DeGeneres and Kara DioGuardi. What is clear is that even before she became an official "Idol" employee, she understood what separates the also-rans and wannabes from the singers who make it to the very end.

"When [viewers] watch you guys every night, they're like, 'Who's going to give me goose bumps?,' " she told the final eight. "It doesn't necessarily mean the one who hits the highest note. It's the one who makes them feel good."

How do you think J.Lo will do on "Idol"? Tell us in the comments!

Don't miss our "American Idol" live stream "Judging the Judges: An 'Idol' Without Simon," featuring post-show analysis from Jim Cantiello and special guests, on tonight at 10 p.m. ET. Tweet your "Idol" commentary with the hashtag #idolwithoutsimon and we could quote you on the show!

Get your "Idol" fix on MTV News' "American Idol" page, where you'll find all the latest news, interviews and opinions.