Marvel has formally announced via Marvel.com that Bradley Cooper is signed, sealed and delivered to flex his vocal chords and join the Marvel universe as Rocket Raccoon in Guardians of the Galaxy.

Cooper had been rumored to be negotiating for the role over the past week while Marvel kept mum about any potential official signings. In scoring Cooper, Marvel adds an Oscar-nominated actor for Silver Linings Playbook and someone no stranger to stardom and big box office returns having starred in the billion dollar plus Hangover Trilogy. Rocket Raccoon marks Cooper’s first foray into the world of voice work.

Cooper joins Chris Pratt as Peter Quill, Dave Bautista as Drax, and Zoe Saldana as members of the Guardians of the Galaxy. Production on the final Marvel Cinematic Universe Phase 2 film before 2015’s Avengers: Age of Ultron has been underway for over a month with James Gunn directing.

With Rocket Raccoon cast, the lone remaining unconfirmed voice role in Guardians of the Galaxy is that of the walking tree, Groot. Vin Diesel has been attached to this role dating back to July, and within the past couple weeks Diesel put up a comic book image of Groot on his Facebook page. It was quickly removed.

Marvel not confirming Groot’s voice actor leads us to believe that negotiations with Diesel or someone else are still ongoing.

Guardians of the Galaxy opens in theaters everywhere next summer on August 1, 2014.

Source: Marvel