Reba McEntire, Monica, Sia Join 'The Voice' As Judge Advisors

Reba McEntire performs onstage at the 44th Annual CMA Awards at the Bridgestone Arena on November 10, 2010 in Nashville, Tennessee.

It's not just about the four musician coaches anymore on NBC's "The Voice."

The network announced on Friday that Reba McEntire, Monica, Sia and music producer Adam Blackstone have joined the series as new advisors who will help "judges" Christina Aguilera, Cee Lo Green, Adam Levine and Blake Shelton in the "battle" rounds.

'The Voice' Premiere: Christina Aguilera Takes the Reins

McEntire will be partnering with Shelton, Monica with Green, and Aguilera will be teaming up with Sia. Levine and Blackstone will be helping their team.

"The Voice" debuted on Tuesday to big ratings, averaging 11.8 million viewers and a 5.1 rating in the adults 18-49 demographic. It was the highest-rated series debut since CBS' "Undercover Boss" early last year. An encore of "The Voice" also performed well, drawing 6 million viewers on Wednesday and snagging a 2.1 rating.

'The Voice' Debut Scores Big Ratings for NBC

The blind auditions continue on "The Voice" next Tuesday from 9-11 p.m. with the following episodes airing after "The Biggest Loser" at 10 p.m.