Leonardo DiCaprio -- Rapping 'Scenario' ... Here We Go, Yo!

Leonardo DiCaprio is definitely not Bo -- because he CAN rap, and he put his skills on full display with a little help from Jamie Foxx.

DiCaprio -- still hiding his face -- was at 1Oak in West Hollywood last Thursday for club owner Richie Akiva’s birthday party ... when he got on the mic to do the classic Tribe Called Quest song "Scenario."

Little known fact -- all males between 35 and 45 know all the lyrics to this song. It sounds like Leo might have temporarily forgotten a few lines, but still ... pretty awesome.

Now here's Busta Rhymes with the ...