PSY -- 'Gangnam Style' Singer DANCES ON THE STREET!!!!

Psy -- the South Korean Internet sensation behind that INCREDIBLE song "Gangnam Style" -- has touched down in L.A. ... and he did the horse dance for TMZ ... RIGHT ON THE STREET!!!

In case you live under a rock ... that doesn't have an Internet connection ... the LMFAO-esque music video for "Gangnam Style" became a smash hit on YouTube -- racking up more than 110 MILLION views since it premiered in July. He recently signed a deal with Scooter Braun -- Justin Bieber's manager.

And last night, Psy -- whose English is pretty damn good -- rolled over to Katsuya in Hollywood ... where he gave our photog an impromptu lesson on how to execute his signature dance move.

And for those non-Korean speakers out there ... Psy finally tells us what he's actually singing about!

It's awesome ... watch the video ... and then treat yourself to this ... just one more time.