03/08/2011 02:09 pm ET Updated May 25, 2011

Jeffrey Donovan Cast As Bobby Kennedy In 'J. Edgar'

Jeffrey Donovan has big shoes to fill.

The "Burn Notice" star has joined the cast of Clint Eastwood's "J. Edgar," a biopic of longtime FBI director J. Edgar Hoover. Donovan will play Bobby Kennedy, confirming the news in a tweet, writing, "I fly to LA Sunday. I have been cars as Bobby Kennedy opposite LD in HOOVER. excited. :-) working with Mr Eastwood again. Dreams come true."

Donovan worked with Eastwood on "Changeling," playing Captain J.J. Jones.

Leonardo DiCaprio stars as J. Edgar Hoover, while Armie Hammer plays Clyde Tolson, Hoover's associate FBI director and rumored gay lover.

Because filming of the movie is already underway, given Donovan's late casting, there may not be a huge role for Kennedy in the film. That said, Hoover had a strong dislike of Bobby Kennedy, who during his brother's administration forced Hoover to fight organized crime instead of communism.

"He considered him an outrage. He thought he was a loose cannon he could not control and he loved being in control," RIchard Hack, author of "Puppet Master: The Secret life of J. Edgar Hoover," told NBC back in 2004.