NBC will air the singing competition as a holiday strip to air over several nights later this year.

Nick Lachey is returning to NBC's The Sing-Off for a fourth round.

Additionally, Grammy nominee Jewel will join the singing competition series' recently announced fourth season as a judge alongside returning stars Shawn Stockman and Ben Folds, The Hollywood Reporter has learned.

Jewel replaces Sara Bareilles, who stepped in for Nicole Scherzinger in the show's third season.

PHOTOS: Broadcast TV's Returning Shows 2013-14

"There are very few musical artists as accomplished and talented as Jewel. Her addition to The Sing-Off judges panel, along with our stellar team of Shawn Stockman and Ben Folds, raises the showmanship of the series up another notch," said Paul Telegdy, NBC's president of alternative and late-night programming. "The musical credentials of Nick Lachey are extraordinary, and his continued contributions to the show as host remain a huge asset."

The NBC entry will now revert to its original broadcast pattern, airing as a holiday strip over several nights later this year. The move marks a return to how The Sing-Off first launched in 2009, when it aired in December as a five-night event. It became a weekly series in 2011.

"I am so thrilled to welcome Jewel to our expert musical panel," executive producer Mark Burnett said. "Jewel is one of America's greatest singer-songwriters and is an amazing storyteller. In company with the incredible talent of Ben Folds, Shawn Stockman and Nick Lachey, this season of The Sing-Off is sure to be its best yet."

For Jewel, the gig comes after she starred in Lifetime's June Carter Cash biopic Ring of Fire and months after she released her greatest hits album. This marks her latest job in the reality genre. She served as a co-host and judge alongside Kara DioGuardi on Bravo's short-lived Platinum Hit songwriting competition series and was a co-host for one season of USA Network/NBC's Nashville Star.

NBC renewed The Sing-Off for a fourth season in March after more than a year off the schedule.

E-mail: Lesley.Goldberg@THR.com

Twitter: @Snoodit