Keanu Reeves & Laurence Fishburne: John Wick in the Matrix??

Keanu Reeves and Laurence Fishburne are going back to the well -- the BILLION dollar well they hope .. for the the action sequel "John Wick 2."

Neo and Morpheus reunited on a Brooklyn rooftop where they're shooting the action-adventure flick. The 'Matrix' trilogy duo haven't co-starred since 2003 when the last film of that franchise was released.

The first "John Wick" made a bundle, more than $80 mil worldwide -- so why bring in Laurence? He and Keanu hauled in more than $1.5 billion with their Matrix work!