Kiefer Sutherland is back on one of his sober kicks – after falling into a depression over his music mentor Tom Petty, Breaking Celebrity News has learned exclusively.

Sources say Petty’s unexpected death earlier this month really hit the 24 star hard.

“There’s hope from the people around (Sutherland) that he can kick his nasty booze habit once and for all on the back of this tragic news about Tom,” an insider told Breaking Celebrity News. “Kiefer loves to party and have a good time, but he’s not self-destructive and wants to live a long life.”

As Breaking Celebrity News readers know Sutherland has had a turbulent history with booze that includes multiple DUIs and a 2007 arrest.

But that’s all changed since Petty passed, a pal reveals.

“Tom’s demise has been a wake-up call for him, and he hasn’t put down his guitar — or picked up a bottle — since.”

While Sutherland and his musical hero weren't exactly close friends, Petty was aware of the actor's fandom, and often encouraged him to try his hand at some of the classic Heartbreakers tunes.

“For several months he and his backup band have been rehearsing and playing a bunch of Tom Petty songs,” the insider told Breaking Celebrity News. “Kiefer has been obsessed with the guy for pretty much his whole adult life.”

We pay for juicy info! Do you have a story for Breaking Celebrity News? Email us at tips@Breaking Celebrity News, or call us at 800-344-9598 any time, day or night.