The battle rounds begin and the coaches enlist the help of the music industry's top recording artists to offer their knowledge and skills as advisors. Christina Aguilera teams up with Patti Labelle, Adam Levine with Tori Kelly, Blake Shelton with Gwe... (more)n Stefani and Pharrell Williams with Sean "Diddy" Combs aka Puff Daddy. In this phase, the coaches pit two of their own team members against each other in a dueling duet. After the vocal face-off, each coach must choose which artist from their team is the strongest, and has the option of stealing losing artists from an opposing coach. Each coach has two steals during the battle rounds where their artists will proceed to the knockout rounds.