"I'm working on some new music that I don't think anyone expects to be the type of music I'm working on," she told PEOPLE at a press event for her new show, Rising Star, Monday night.
With her co-expert Brad Paisley digging for details and offering to get her a cowboy hat in case she decides to go country, the "Crazy Kids" singer, 27, played coy about her new sound, simply saying, "I feel like I have a lot to do!"
The pop star has been stepping back into the spotlight since completing rehab for eating disorders earlier this year and is looking forward to mentoring talent alongside Paisley on ABC's new singing competition.
"It's terrifying for those kids," she said. "I feel so bad for them, but I'm really excited. I think people would be surprised how different I would like the talent to be. I want country, I want polka – all of it!"
For now, both Paisley, 41, and Kesha are still figuring out their judging styles, but one thing's for sure – there will be no shortage of personality.
"I'm not mean, but I am honest and I can't help it," she said. "I have no filter. It just comes out of my mouth."
Added Paisley: "She has no problem being honest. I might have a problem, but [our role is] less about being that person that decides someone's fate and more about helping them get their best self out there."
Rising Star debuts Sunday (9 p.m. EST) on ABC.