The famous brothers look back on their childhood in this funny new interview.

First-time director BEN AFFLECK and his brother CASEY AFFLECK are sitting down for a funny, no-holds-barred interview for their new Boston-based movie 'Gone Baby Gone' -- in theaters Friday -- and ET has the exclusive footage! Find out what it was like to "grow up Affleck" and how Ben "caused" Casey to break his arm as a kid at AOL moviefone's "Unscripted" site!

The compelling drama is based on the book by Mystic River writer DENNIS LEHANE and was adapted by Ben and screenwriter AARON STOCKARD. Of course, Ben landed an Academy Award for co-writing 'Good Will Hunting' with good pal MATT DAMON.

'Gone Baby Gone' is also a family affair, with Ben's younger brother CASEY AFFLECK ('The Assassination of Jesse James by the Coward Robert Ford,' 'Ocean's Thirteen') in the lead. Ben spoke highly of Casey telling ET "My brother is an exceptional actor." He also gave his cast all the credit saying "I was honored to be among them."

The film tells the story of a pair of private investigators (Casey and 'M:i:III' star MICHELLE MONAGHAN) searching for an abducted four-year-old girl in Boston's seamy underworld, where nothing is as it seems.

It also stars MORGAN FREEMAN, AMY MADIGAN and ED HARRIS.