'Goonies' Sequel Steven Spielberg's Brainchild ... Says Richard Donner

EXCLUSIVE

Watch your words Corey Feldman ... 'cause "The Goonies" sequel director Richard Donner says he's working on is NOT some rogue side project -- he's working with Spielberg.

Donner tried playing mum on more sequel talk Friday while cruising Beverly Hills -- after he let the cat out of the bag earlier this month -- but the director couldn't contain himself when we asked if Steven Spielberg was also involved.

As we previously reported, Donner wants the original cast to return -- and now that he's got Spielberg behind him ... we're guessing Josh Brolin might be willing to read the script.

HEY YOU GUYS ... it's finally happening!!