David Hasselhoff has fallen off the wagon once again ... TMZ has learned -- this
time making a drunken spectacle out of himself during a trip to Canada this
weekend.

We know the Hoff -- who's famously struggled with alcohol in the past -- was
drunk in British Columbia over the weekend and caused a scene.

Multiple sources tell us it all went down at the Cascade Casino, when The Hoff
somehow got himself involved in an altercation with an elderly patron.

We're told three casino security personnel were called to the scene ... and Hoff
was eventually escorted away.

But here's the most shocking part ... We're told Hoff was seen drinking again
just 7 hours later.

So far, no comment from Hoff's camp.