We previously reported that Bradley Cooper (Silver Linings Playbook) was in talks to voice Rocket Raccoon in James Gunn's Guardians of the Galaxy ... and then we confirmed that, yes, he was indeed in talks.  Now, since nothing is official until it's stamped by Marvel, we can report that Cooper has indeed joined the ambitious picture as the voice of the anthropomorphic raccoon.

The cast of Guardians of the Galaxy, which opens August 1, 2014, also features Chris Pratt, Zoe Saldana, David Bautista, Glenn Close, Michael Rooker, Lee Pace and John C. Reilly, and maybe Vin Diesel if and when we hear that he's officially voicing Groot.  Hit the jump for more.

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Here are the particulars from Marvel.com:

Rocket Raccoon has finally found his voice!

Academy Award-nominated actor Bradley Cooper has officially joined the cast of Marvel's "Guardians of the Galaxy," lending his voice to the fan-favorite raccoon that will join Peter Quill (Chris Pratt), Gamora (Zoe Saldana) and Drax (Dave Bautista) on their epic adventure.

Cooper has previously starred in "Silver Linings Playbook," for which he was nominated for an Oscar®, "Limitless," "Place Beyond the Pines" and the "Hangover" trilogy, the latter of which has grossed $1.4 billion globally. He will next be seen in "American Hustle" which will reunite him with "Silver Linings Playbook" director David O. Russell. "Guardians of the Galaxy" will mark Cooper's first voiceover work.

In the far reaches of the Marvel Cinematic Universe, an unlikely cast of characters including Peter Quill, Gamora, Drax, Groot and Rocket Raccoon must join forces to defeat a cosmic force of epic proportions. Directed by James Gunn, the live-action "Guardians of the Galaxy" will take fans to new corners of the Marvel Universe when it hits theaters August 1, 2014, but in the meantime stay tuned to Marvel.com for the latest news as it breaks, including official casting, first looks and more!

In addition to "Guardians of the Galaxy," Marvel Studios will release a slate of films based on the Marvel characters including "Thor: The Dark World" on November 8; "Captain America: The Winter Soldier" on April 4, 2014; "Avengers: Age of Ultron" on May 1, 2015; and "Ant-Man" on November 6, 2015.