Sara Bareilles departing "The Sing-Off"

Sara Bareilles is signing off of "The Sing-Off."

According to Entertainment Weekly, Bareilles is leaving NBC's a cappella singing competition series so she can "focus on her music," says a source close to Bareilles.

The Grammy-nominated singer-songwriter replaced original "Sing-Off" judge Nicole Scherzinger for the show's third season after Scherzinger departed to Fox's "X Factor."

The show is reportedly being overhauled for its upcoming fourth season by its new executive producer -- Mark Burnett, the brains behind the "The Voice" and "Survivor." And Barielles' departure will shake things up even more, as they will have a new hole to fill at the judges' table.

"'The Sing-Off' showcases great talent and a musical form I love," Burnett said last month. "It's very special, and we're excited to be involved."

The show premiered in December 2009 and has had its fair share of ups and downs in the ratings -- including almost being canceled in 2012. But last month NBC announced "The Sing-Off" would return sometime during the holiday season. The series currently stars host Nick Lachey, and judges Ben Folds and Shawn Stockman -- and hopefully they'll stay put for the upcoming revamped season.

Tell us: Are you excited that "The Sing-Off" is returning? Will you miss Sara Bareilles?