Walt Disney Animation Studios, in a significant leadership shift, on Thursday named Academy Award-winning filmmaker Jared Bush as its new chief creative officer, effective immediately.

Walt Disney Animation Studios is replacing Jennifer Lee, its chief creative officer, after an uneven six-year tenure.

Lee is writing and directing “Frozen 3” and writing “Frozen 4” with Marc Smith — the sequels to Disney Animation’s 2013 “Snow Queen”-inspired cultural hit “Frozen,” for which she served as writer/director. The movie made $1.3 billion worldwide and earned two Oscars, for best animated feature and for earworm song “Let It Go.”