Justin Guarini is returning to TV -- sort of.

The first-season American Idol runner-up will be starring in his own commercial for Diet Dr. Pepper, Us Weekly reported.

Guarini's comedic commercial is being made 13 years after he competed on Idol back in 2002 and lost to winner Kelly Clarkson.

In the commercial, Guarini plays a fairly-like character with long, red, curly hair called Lil' Sweet, who carries a tambourine. He's wearing a sparkly silver costume with a scarf and fingerless gloves.

When a woman in her office laments she wants something sweet without a lot of calories, the 36-year-old singer reportedly appears, says his own name in a high-pitched voice, and then offers her a no-calorie Diet Dr. Pepper with a cheesy line. Guarini also shows off his vocal ability through some addd riffs.

Guarini has been making a living since his stint on Idol by performing in many Broadway and theatrical productions.