Shore had previously worked with Jackson on all three of the "Lord of the Rings" movies, earning three Oscars in the process.
In a statement released by Universal Pictures, director Peter Jackson said, "I have greatly enjoyed my collaborations with Howard Shore, whose musical themes made immeasurable contributions to 'The Lord of the Rings' trilogy. During the last few weeks, Howard and I came to realize that we had differing creative aspirations for the score of 'King Kong.' Rather than waste time arguing with a friend and trying to unify our points of view, we decided amicably to let another composer score the film. I'm looking forward to working with James Newton Howard, a composer whose work I've long admired, and I thank Howard Shore, whose talent is surpassed only by his graciousness."
Source: Universal Pictures

