See Clay Aiken and Ruben Studdard Slip Back Into Their 'American Idol' Gear, 15 Years Later

Clay Aiken and Ruben Studdard give American Idol fans a blast from the past in their new Broadway show, and PEOPLE has the exclusive first-look.

The two former competitors, who went head-to-head on season 2 of the hit singing competition series, have joined forces for a new limited stage show, Ruben & Clay’s First Annual Christmas Carole Family Fun Pageant Spectacular Reunion Show — a night of sketch comedy and holiday songs that’s now open at New York City’s Imperial Theatre.

On stage, the duo, both 40, sound as though Idol was just yesterday, their voices perfectly intact.

And they look a lot alike too, slipping into their old Idol gear during one scene.

Aiken wears a similar cream-colored stripped button-down and khaki pants that helped earned him the love of Claymates everywhere.

Meanwhile Studdard is once again in a red “205” jersey, the numbers calling out the Velvet Teddy Bear’s Birmingham, Alabama, hometown.

“Ruben looks great in his,” Aiken tells PEOPLE. “But I’m not gonna lie… Mine probably had to be let out a little.”

Though Aiken and Studdard went up against one another on TV — with Studdard taking the crown — neither felt any rivalry behind the scenes.

“I think it was hard to have that kind of competitive spirit in the way that they had that set up,” Studdard explains. “It felt more like a dorm room.”

“I don’t think we ever felt like competitors on the show, nor since,” says Clay. “We play it up for fun but it’s never been that way for us. We went through this process where, nobody had really done it before. All of us just thought it was going to be a fun experience and nothing else. We didn’t realize there were stakes involved. So we really became friends throughout. I was just as happy to see Ruben win as I would have been had I won.”

The two have remained pals over the years, regularly keeping in touch despite their differences.

Says Aiken: “We all have just one or two people in our lives who, no matter how long we may be away from them, make coming back together feel like we had only been apart for a few days. Ruben is like that for me. He’s easily the person who I feel the most kinship and natural rhythm with on stage. So even though it’s been so many years since we have sung together, it really feels like putting on favorite slippers.”

“We are both very different creatures,” Aiken continues. “The things that are important to him — the things he is very particular about — always tend to be things that I am not. And the reverse is true also. But we both know that the other is always gonna look out for us. That trust and loyalty is almost impossible to find. Ruben is that guy.”

“I feel — and I hope and believe Ruben feels the same — safe and protected with Ruben,” Aiken adds. “We still argue all the time, but on stage with Ruben, I never worry. We always look out for each other. If I drop a line, he’ll cover for me. If I hit a bad note, he’ll change what he’s singing to make me sound like I was right. He knows I’d do the same for him.”

For more on Aiken and Studdard, pick up this weeks issue of PEOPLE, on newsstands Friday.

And as for others auditioning to the new, rebooted season of American Idol? Studdard suggests they embrace the opportunities that come with the show.

“Many of the young people who audition have been trying to break into the industry. American Idol gives you a platform that shows your talent to such a broad scope of people,” he says. “Even if you don’t win, you notice that there are seven of us who are alums who have had jobs in so many different kinds of industries because of our time on the show. It really opens the doors for people like us who traditionally didn’t have a way to break into the industry.”

Ruben & Clay’s Christmas Show is playing through Dec. 30. Tickets are available now.

In true holiday spirit, a portion of all proceeds will go to benefit the National Inclusion Project, the leading voice for the inclusion of children with disabilities.