The iconic Clint Eastwood turns 84 years old this year, and while he has largely retired as an actor - last seen in front of the camera in 2012's Trouble with the Curve, the feature debut of his longtime first assistant director Robert Lorenz - as a director he has shown no signs of slowing down.

In the decade since the Best Picture Oscar-winning Million Dollar Baby, Eastwood's diverse (and sometimes uneven) output included two great World War II films (Flags of our Fathers and Letters From Iwo Jima), a massive blockbuster hit with Gran Torino (over $269 million worldwide) and Invictus, which starred Morgan Freeman as Nelson Mandela.

The director's first film since 2011's biopic J. Edgar is an adaptation of the hit Broadway musical Jersey Boys, which follows the story of the legendary pop group Frankie Valli and the Four Seasons.  Watch the first full-length trailer above.

Eastwood, who had been developing a modern update of the often-remade A Star Is Born, took over directing duties on Jersey Boys after Iron Man director Jon Favreau left the project. The popular perception is that after Beyoncé Knowles dropped out of A Star Is Born (which would've been the fourth version of the story since 1937), Eastwood quickly boarded the other musical.

Jersey Boys Frankie Valli and the Four Seasons

Jersey Boys diverges from the usual casting of Hollywood versions of Broadway hits by retaining the star of the Tony-winning stage show's original cast with John Lloyd Young playing frontman Frankie Valli. Additionally, Vincent Piazza is Tommy DeVito, Erich Bergen plays Bob Gaudio, with Michael Lomenda as Nick Massi. As an added bonus, Christopher Walken appears as mob boss Angelo "Gyp" DeCarlo.

Original Four Season Gaudio developed the stage musical, which contained biographical elements of the group not widely known during the group's heyday (such as the prison records of several members), a unique detail which helps to explain the show's popularity.

The film's trailer shows off the group's development of their ground-breaking style, along with a good amount of the story - along with the Rashomon-style conflicting narration, often delivered straight to the camera, which breaks the fourth wall, bringing an interesting meta-aspect Eastwood has never used before.

While Jersey Boys at first seems like an odd choice for Eastwood, he actually starred in the 1969 Western musical Paint Your Wagon, which was a notorious bomb. He has an affection for big, old-fashioned Hollywood productions, and from what we can see in this first trailer, Eastwood's straight-forward, no-nonsense directing style might actually mesh well with the melodrama and inherent artifice found within a musical.

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Jersey Boys opens in theaters on June 20th, 2014.