Christina Aguilera was on the Tonight Show last night to remind everyone that's she's back to be a judge on The Voice. Jimmy Fallon brought out the impression wheel for a sing-off. Aguilera started with a pretty damn good Cher impression set to Folgers. But let's not kid ourselves, we're all here to listen to her do a perfect Britney Spears impression—only after she gives a little look of disgust for being asked to stoop as low as her fellow Mickey Mouse Club nemesis Mouseketeer—and it's perfect.

Cruel points: Aguilera sings "My Little Piggy" set to the tune of "... Baby One More Time." Fallon had to collect his brain from his desktop. And since he was following up Aguilera-Spears with a Michael McDonald impression, it was only fitting that his brain was all scrambled.