By Jessica Herndon
November 05, 2010 09:30 AM
ark Davis/Fox/PictureGroup

Note to contestants hoping to impress American Idol judge Jennifer Lopez: Don’t sing her songs.

“It was cute, super entertaining and flattering, but no,” the pop diva says of contestants who failed to make it through auditions by performing one of her hits.

“They know we’re not out to cut them down or make a joke of them,” she told reporters Thursday at a stop in Los Angeles. “We’re trying to mentor them to the next step.”

And so far – after visiting seven cities – Lopez says they’ve found 15 to 20 “real superstars who could be recording artists for sure,” adding that the judges have seen “a lot of great country [singers].”

RELATED: Jennifer Lopez Is the ‘Alpha Female’ at the Judges’ Table, Says Idol Producer

Just like in the show’s previous nine seasons, for every potential “superstar” there are dozens of contestants who have to hear bad news from the judges – which can sometimes be heart-wrenching.

“I’ve cried,” Lopez said. “We get a lot of elation when we put them through and devastation, almost, when they’re not. But it’s been a ball.”