Secrets Of 'The Voice': Who Refused To Return, & Who's Making $14M!

The competition is getting intense on the current season of NBC's hit singing reality competition show, The Voice! But RadarOnline.com has exclusively learned that the onstage drama is nothing compared to the battle going on behind the scenes with the coaches! Click through 7 shocking photos to find out all the secrets and shakeups, including who's in, who's out, and who is getting paid millions more than the others!

This season's cast — coaches Adam Levine, 38, Blake Shelton, 40, Gwen Stefani, 47, and Alicia Keys, 36 — did not deliver the type of ratings that the network was hoping for, and according to an on-set source, some major changes had to be made for next season. As fans know, American Idol alums Jennifer Hudson and Kelly Clarkson announced last week that they will be joining the cast.

"Blake and Adam are definitely back on for season 13," said source. "The network offered them both contracts that they could not refuse. It was for several million more than they were making, which was $13 million each for season 12."

As RadarOnline.com reported, Shelton's girlfriend, Gwen Stefani, replaced Miley Cyrus, 24, as a judge on the panel this season. Now Cyrus is coming back, but Stefani refused to coach alongside the "Wrecking Ball" singer.

"Gwen would not be on with Miley at the same time," the source explained. "Gwen has not made any plans to return to the show after this season, even though Blake is coming back. She feels like her time on the show has ran its course, and she is going to focus on her family and music career."

But what about Kelly Clarkson? Last week, the 35-year-old chose The Voice over her alma mater, American Idol, but she won't be coaching until season 14. "Kelly would not be on with Miley either, and there was actually a bidding war for her," said the source, adding that she'll be raking in a whopping $14 million.