Justin Guarini

American Idol alum Justin Guarini is getting married on Saturday.

The singer will exchange vows with fiancée Reina Capodici in an intimate ceremony on a private estate along the Delaware River, near their families' homes in Pennsylvania.

Guarini, 30, and Capodici, 27, have known each other since high school, but only started dating a few years ago and made marriage plans in December. Capodici has a 4-year-old daughter, Lola, from a previous relationship.

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The couple has written their own vows for the "spiritual" service, which will be presided over by a female minister from the Universal Church. The Vitamin String Quartet will perform special arrangements of songs by such artists as Radiohead, Paramore and Peter Gabriel in lieu of traditional wedding music.

See photos of Guarini through the years

Guarini, who finished second to Kelly Clarkson on Idol, covered the Emmys last weekend for TV Guide Network. He also hosts TV Guide Network's Idol Tonight series and has been doing a sketch comedy show for www.sketchedouttv.com. He plans to record his third album this winter.