The 15-time GRAMMY winner is returning to The Voice in February for her third season as a coach, after scoring a victory with contestant Chris Bluein season 12. This time around, she'll face off against Shelton, Adam Levine and Kelly Clarkson for top bragging rights -- but she's ready.
"I have to come back and put him in his place, man," Keys cracks, referring to Shelton's win last season with Chloe Kohanski.
"He is slightly crazy right until the end," she jokes. "Like, it's at the end that he starts to become this secret villain that's trying to win."
"No one can save him," she says. "He's unsavable."
While Stefani sits this season out, Keys says that she and Clarkson are ready to bring the girl power.
"I'm all about the girl power and, you know, the whole world is about girl power because, as we see, clearly we need us badly to make sure our powers' intact so the world can be safe," she says. "We are just genuinely supportive of each other. She's such a magnificent -- what a crazy, amazing beautiful voice, you know, and person. It's all that in there, plus she's kinda silly like me, so I think we really get along just in a super natural way."
ET caught up with Keys while working with her team on the Battle Rounds earlier this month. In Team AK's corner this season is pop phenom Shawn Mendes, who serves as her celebrity advisor.
"It's an honor, first of all," Mendes said of being asked to join Keys. "I feel like I should be getting in front of the microphone and singing, and asking her for advice! I think there was one moment that I was sitting there halfway through a song, and I'm like, 'Am I really sitting here right now, like, with her being an advisor? I'm 19 years old!' This is really crazy."