Justin Guarini, American Idol season one alum, is making a return to television!

The Idol runner up is back on television after 13 years. Instead of competing in a reality show, Guarini is starring in an advertisement.

The Diet Dr. Pepper ad features Guarini as a Lil' Sweet, a costumed fairy like character that is dressed like a rockstar. Guarini appears four seconds into the ad, sliding in on his knees, singing his name in a high-pitched tone, wearing a maroon wig, matching pants and scarf, a silver jacket, and fingerless gloves. He also carries a tambourine. "Did someone ask for the sweet no-cal sweetness of Diet Dr. Pepper?," he asks.

The 36-year-old is currently starring in a stage revival of Paint Your Wagon. Since filming Idol in 2002, Guarini has found success on the stage, starring in American Idiot and Women on the Verge of a Nervous Breakdown.

Since filming American Idol, Guarini co-starred in From Justin to Kelly with the winner of the inaugural season, Kelly Clarkson. Guarini admitted last year to being romantically involved with Clarkson during a Pennsylvania concert, per E! Online.

Image courtesy of Credit: Kristin Callahan/ACE/INFphoto.com