03/27/2015 12:10 pm ET Updated Mar 27, 2015

Yes, That's Justin Guarini In That Diet Dr Pepper Commercial

Justin Guarini is back on the small screen, but he looks very different from his "American Idol" days.

The former "Idol" runner-up makes sweet music as Diet Dr Pepper's "Lil Sweet," looking unrecognizable in a long purple wig in the latest commercial titled "Birthday." Lil Sweet comes to the rescue in the latest 30-second ad spot by bringing the zero-calorie beverage to a cupcake-filled birthday party.

The first Lil Sweet ad debuted in February.

Guarini made a name for himself in Season 1 of "American Idol." After losing to Kelly Clarkson, he went on to co-star with her in the box-office bomb "From Justin to Kelly" and try his hand as a recording artist. He has been performing theater for the past 10 years, including a handful of Broadway shows. In 2013, he wrote a blog post about the struggles of his post-"Idol" life.



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