Justin Guarini is back on TV, showing off his impressive vocal cords in a new commercial for Diet Dr. Pepper.

The American Idol Season 1 runner-up looks completely different in the 30-second clip. Not only is he digitally altered to look small, he donned a maroon wig, hiding his signature curly hair. If it wasn't for the insane falsetto Justin throws down, we might not recognize him at all!

In the video, Justin portrays "Lil' Sweet," -- who is "self-employed" but apparently goes around spreading the gospel of Diet Dr. Pepper. It's hilarious -- and something you should definitely check out in the video above!

The Diet Dr. Pepper commercial went viral just weeks after American Idol Season 1 winner Kelly Clarkson admitted that she briefly dated Justin.

“We didn’t date during Idol, which everyone thought we were dating,” Kelly told Andy Cohen on the March 5 episode of Watch What Happens Live. “We did date during — I feel like we weren’t dating during the movie … We did date a little bit.”

Since his season of American Idol, Justin kept busy by dropping his self-titled debut album, plus a second album and an EP. PEOPLE reports that the singer is now married with two kids -- William Neko, 3, and Asher, 2 -- as well as a stepfather to his wife's daughter Lola. In 2013, he opened up to Oprah about his battle with depression after being dropped by his record label and management company.

See What Kelly Clarkson + More Singers Looked Like When They Released Their Debut Albums

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