Pharrell Joins Gwen Stefani to Perform ‘Spark the Fire’ on ‘The Voice’ [VIDEO]

If you've been watching the new season of 'The Voice,' you'll quickly see the bond that Gwen Stefani and Pharrell have -- even though they're competitors. The two showcased more of their friendship last night (Dec. 1) with the debut performance of the singer's new song 'Spark the Fire.'

Gwen popped up onstage riding on a cute emoji character as the screen behind her filled up with colorful graphics. "Who got the lighter? / Let's start the fire," she sings on the high-energy track.

Pharrell arrived with a torch in his hand, serving as more of a hype man while the songstress delivered her lyrics to the crowd. The two played off each other and showed just how their stage chemistry completely works on the stage.

Get fired up with Gwen and Pharrell above.

Watch Gwen Stefani's 'Spark the Fire' Video Feat. Pharrell