The autograph hound who went nuclear on Jason Kelce outside "Jimmy Kimmel Live!" last night was living up to a reputation he's earned in Hollywood ... as a guy who likes to explode on celebs -- at least according to cops.
Law enforcement and 'Kimmel' security sources tell TMZ ... the guy who's seen on video calling Jason a "p***y" is a regular at the studio and Hollywood premieres, and always shows up when celebs get their stars on the Hollywood Walk of Fame.