Keanu Reeves ' security had to go "John Wick" on an unhinged fan who tried to get in his SUV ... and the whole encounter was caught on video.

The actor was leaving a performance of "Waiting for Godot" on Broadway -- in which he's costarring with his longtime collaborator Alex Winter -- and fans crowded around the stage door to catch a glimpse of the superstar. @amirmeetsny via Storyful

Reeves gets in his car safely ... when a commotion suddenly breaks out -- with a fan rushing to try and get in the vehicle with him while the security that walked him out holds her back.

This woman yells out, "It’s your divine wife!" -- unclear what she means by that ... but it seems obvious she's not thinking with a clear head.

After the security is able to fend her off the first time, this per

See Full Page