Jack Black Yaps With Paps

12/12/2007 4:40 PM PST BY TMZ STAFF
Ever wonder who Paris Hilton is always yappin' to on her cell phone? Portly actor-musician Jack Black shared his theory during an afternoon stroll down Rodeo Drive.

The jolly Jackster -- sportin' a five o'clock shadow and a new blonde 'do -- also took one persistent fan to his impromptu School of Photography. Tenacious!