Britney Spears is channeling her iconic "…Baby One More Time" schoolgirl outfit in her latest Instagram post. The pop star, 37, posted a mirror selfie on Thursday, saying that she had returned ...

in which Tenacious D (a.k.a., Black and long-time collaborator Kyle Gass) bust out an extremely bearded cover of Britney Spears’ “…Baby One More Time” for the soundtrack of Kung Fu Panda 4.