A bomb squad rushed to an Ozzy Osbourne book signing on Friday after a man was caught with homemade fireworks in his backpack. 

The Black Sabbath rocker was signing copies of his autobiography when police officers spotted a man allegedly smoking marijuana at the event in a Barnes & Noble bookstore in Palm Beach Gardens, Florida. 

The man ran off after the authorities approached him, but they later caught him and found what appeared to be homemade fireworks in his backpack, as well as a quantity of marijuana. 

A bomb squad was then called to the scene to dispose of the combustible materials, reports CBS news. 

The man is now facing drug possession charges, according to a police spokesperson. 

But Osbourne's Florida visit wasn't all bad - the Prince of Darkness was handed the key to West Palm Beach earlier in the day in recognition of his long-running career.

Ozzy Osbourne Pictures