9:19am PT by Ashley Lee
'The Voice' Battles: Behind the Scenes With Usher and Adam Levine (Exclusive Video)
Coldplay's Chris Martin may be joining The Voice as a universal advisor for a new round of battles, but not for a couple more weeks.
Meanwhile, the coaches and guest mentors are goofing around plenty in the current round of sudden-death duets, during rehearsals and between performances.
Watch the exclusive clip below to find out what Adam Levine did with his Sexiest Man Alive magazine cover, what gets Usher incredibly tongue-tied, and what male singers have to do to get Jill Scott weak in the knees.