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According to 'Entertainment Weekly,' Sizemore will appear in several episodes of the cop drama's upcoming second season. 'The 'Saving Private Ryan' and 'Black Hawk Down' star will play the head of Hawaii Police's Internal Affairs unit.

After the twists and turns of the debut season, Sizemore's character will be actively investigating the Five-0 unit. A hardboiled former Detroit Homicide Detective, he reportedly won't cut Steve and the gang any slack.

'Hawaii Five-0' was CBS's breakout hit of the Fall 2010 season, and was one of a small group of new network shows to be given a second season.

CBS head Les Moonves is confident that it will become a new cash cow for the network, telling investors last month that the show's poised to become a billion-dollar franchise. Sources estimate that CBS earns $5 million per episode thanks to a recent syndication deal.

Sizemore's movie career has taken a backseat in recent years as he battled substance abuse problems and spent time in jail on drugs offences. In 2010 he and then-girlfriend Heidi Fleiss appeared on a volatile Season 3 of 'Celebrity Rehab With Dr. Drew,' since when he says he's managed to remain sober.

'Hawaii Five-0' Season 2 is due to premiere in September on CBS.