The Aerosmith frontman, 62, says fans of American Idol will see that side when the show premieres Wednesday (8 p.m. ET) on Fox and he takes a seat at the judges' table alongside Jennifer Lopez and Randy Jackson.
"It would be like if I had cameras in my house when my kids were growing up," he says of his Idol experience so far. "I get to be more vulnerable, honest, open and more in the moment."
Though Tyler was consumed by his sweet side when judging began, the rocker says he quickly snapped into critical mode – especially when nearly 15 contestants tried singing his own hit, "I Don't Want to Miss a Thing."
"When I didn't like it I felt ill at ease to tell them, 'You really didn't sing it good,' " he says. "But after the third or fourth, I got into it." He's since narrowed down his judging criteria to three main elements: "Can they sing? Are they in pitch? Do they have star quality?" he says.
And so far, at least one contestant is rocking Tyler's world.
"One kid has a rock element," he says. "His voice is ridiculous, crazy and great. He's totally off the wall. I don't know which rock star ever wasn't, but I got hopes he makes it through."