He's made two CDs and released four hit singles. Tonight, Aiken returns to the tube to make a guest appearance on the NBC sitcom "Scrubs." On Feb. 25, he comes to O'ahu to perform in a fund-raising event for his favorite charity, The Bubel/Aiken Foundation, at the Sheraton Waikiki.

While "Idol" graduates have gone on to varied successes in their post-Simon careers, Aiken is a bona fide star. It's a tag he accepts with responsibility.

"Every celebrity should hope to be a role model to kids, to teenagers, to young adults," he said in a quick phone interview from Los Angeles. "I talk about the causes that are important to me now, things that matter to me, and I'm in a position to help."

The Bubel/Aiken Foundation provides grants, services and programs for children with special needs. The foundation was co-founded in 2003 by Aiken and Diane Bubel, a parent and disability activist, whose son Mike has autism.

The foundation's mission matches up with Aiken's pre-"Idol" life, when he was a special-education teacher and mentor working in Raleigh, N.C., his hometown.

That experience, however different from his current life as a music star, has helped him understand show biz a bit better, he said.

"Special ed teaches you to deal with different kinds of people with special needs," he said. "The biggest factor you learn is the need for patience; it takes time to work with these youngsters. In the arena of show business, patience also is necessary."

At the foundation dinner, he will perform briefly and also speak.

"The message I'll share is that inclusion is extremely important for kids with and without disabilities — to experience life activities, to participate in change together ... with peers who normally might not be able to participate. The exposure to a diverse population helps make them more open-minded; the experience brings new ways to look at individuals and peers."

Aiken is a swift talker, firing off sentences at a rapid clip — all with that calming and cordial Southern-hospitality drawl. To any viewer of Fox's "American Idol," the voice makes him immediately recognizable, even without the disheveled red hair that appeared as part of his makeover en route to the finals in 2003.

He's a lot more animated and eloquent about his post-"Idol" life but tends to avoid lengthy comments or precise details about the talent competition, its organizers, its judges.

Clay Aiken guests on "Scrubs" as a contestant in a segment taped before a live audience. It airs at 8 tonight on KHNL. Paul Drinkwater • NBC

CLAY AIKEN Full name: Clayton Holmes Aiken Age: 26 Birth date: Nov. 30, 1978 Hometown: Raleigh, N.C. Hair color: Red Eye color: Green Education: Majored in special education at University of North Carolina (Charlotte) Discography, CDs: "Measure of a Man," "Clay Aiken Christmas." Singles: "The Way," "Solitaire," "Bridge Over Troubled Water," "This Is the Night"

Joyful Noise tour.

"None of this was anticipated when I was on 'Idol,' " he said. "At times, it was a nerve-wracking experience. But I had no clue about what to expect."

Stardom has meant that he's had to sacrifice his privacy, "but the pluses of appearing on the show are obvious," Aiken said. He was a virtual unknown until "Idol" made him an instant household name, enabling Aiken to launch a solo career.

Perhaps his simple North Carolina upbringing was a factor, too.

"I try to be honest and open and true to myself," he said. "But (the fishbowl existence) means the people see everything I do and watch my every move and behavior. They take notice."

Since the contest and his career launch, Aiken said he's become savvy and cautious about relationships.

"You get into this arena, and you kinda have to watch who your friends are, who to keep in touch with, who to avoid."

He defends the grip "Idol" has over its stars — including its rigid circle of protection and access — and denies there's anything questionable about the show's tactics.

Asked if he was happy to be a free agent, no longer subject to the clutches of the "Idol" producers and camp, he said it's only perception that he, or any other "Idol" contender, was manipul-ated.

"They don't own anybody," he said. "You're under contract with 'Idol,' and when it's up and when the tour's over, you're free."

Nowadays, Aiken doesn't hang out with the show folk or communicate with judges Randy Jackson, Paula Abdul or Simon Cowell. "We talk when we see each other and we have a good relationship," said Aiken. "But we don't go out to dinner together."

Though Aiken will play a singing contestant on NBC's "Scrubs," he says there's not much on his radar the rest of the year.

"I'm just starting to think about the next album cycle," he said. "It's in the premature stages right now, to do the second regular studio album. I'll take some time off the rest of the year; there are no tours planned."