Ke$ha thinks Britney Spears is a huge let down to her fans -- for lip-synching her way through live shows.
America's pop-squeak told UK's Daily Record recently: "[Lip synching] is treating people as if they are too stupid to realize you are not actually singing ... I don't want to treat my fans like they are stupid."
Baby Gaga claimed she'd never rely on lip-synching at a live show. As for if that's a good idea ... jury's still out.