The singer-and-actress has joined the panel along with Aerosmith frontman Steve Tyler and insists she hasn't been going easy on the pop hopefuls since the auditions began.
Jennifer, 41, described her judging style as "tough, easy and fair," adding: "I really want to put them through the wringer in the sense that I don't want to let anybody really great go because they're nervous or whatever and not get to see what they could've been.
"We working with them a little more than maybe you've seen in the past. We give them more of a chance."
The show started filming auditions at the end of September in Los Angeles, and has recently moved to New Jersey where J.Lo warned prospective contestants she is looking for more than just vocal talent when she judges them.
Their look and style are also very important to her – although she won't give out any specific tips as to what she's looking for.
She said: "It's definitely part of a package when you're going to be an artist, but I can't tell you what that would be because it's a very personal, individual thing."
Tyler has also been trying to judge the contestants "fairly", but has advised anyone whose audition isn't successful not to direct their frustration at the judging panel, which also includes Randy Jackson.
He said: "Don't get mad at what we say. Get better!"