Steven Tyler became a rock idol in the 1970s, long before reality television even existed. And now he's joining 'American Idol,' the biggest reality show to ever hit these shores. As a judge, he'll be helping America choose their next 'Idol' through a competition. It's certainly a different journey.

"I always thought that in order to become an American Idol, or any kind of idol, you have to pay your dues," Tyler said on 'Late Show' (Weeknights, 11:35PM on CBS), referring to the years of national touring he did with Aerosmith. "But, today's a different world."

"I prefer the process that gave us you to this process," David Letterman said of 'American Idol.' "By the time you're ready, you're ready, and we have the honest, legitimate stamp of approval."

Tyler responded, "I tend to agree," which was enough to get uproarious applause from the crowd. Surely FOX couldn't be too pleased that one of their newer high-profile judges is basically saying he doesn't think this is the best way to find a new music idol?

Legitimacy as a vehicle for creating music stars has been a driving focus of the show since day one. And never has it been more essential than now, when it's been a few years since an indisputable star has come from the show.

Tyler does qualify -- or, should we say, clarify -- his statement. "This way is more fun," he says, referring to the 'Idol' process. "It's more excruciating -- we get to put 'em through hell and they do it, and they come out the worm-hole looking good. You'll see."

But is it enough to dampen the fact that he agreed with Letterman's assessment of the validity of what 'American Idol' is hoping to create? For the few genuine stars they have found, the number of not-so-much finalists is growing. Even recent winners have failed to impress.

Then there's the fact that his clarification only indicated that 'American Idol' is fun for the torture the contestants go through to try to achieve their dreams. In other words, it makes for good television. That doesn't mean it makes for great musicians.