Fans of The Voice know that a huge part of being a coach is the ability to convince a coveted singer to join their team. And even though Gwen Stefani and Pharrell Williams may be new to those big red chairs, they seem to be catching on very quickly. In this sneak peek from Monday's Season 7 premiere (8/7c, NBC), No Doubt's leading lady and the "Happy" singer each must give their absolute best sales pitches to win over a soul singer who gets all four coaches to push their buttons.