She's a “knockout”: Mariah Carey to serve as key advisor on “The Voice”

Trae Patton/NBCMariah Carey is joining The Voice starting next week.

The diva will serve as a key advisor for Season 15’s Knockout Rounds on October 29. She’ll work with and mentor the remaining 32 contestants, along with coaches Kelly Clarkson, Jennifer Hudson, Adam Levine and Blake Shelton.

In the Knockout Rounds, the contestants will have to compete against each other in pairs, but each contestant will choose their own songs, which they’ll perform individually; their competitor will then have their turn to do the same.  The goal is to have their coaches choose them for