Orlando Bloom threw a punch at Justin Bieber early Wednesday morning in Ibiza ... and Justin fled the restaurant....

You don't actually see the punch but you see the scuffle after the fact...

When the video starts you hear Justin scream, "What's up bitch?"

Justin partied with Orlando's then-wife Miranda Kerr after a 2012 Victoria's Secret fashion show in NYC and got a little to close for comfort...Then of course Orlando was seen hanging out with Selena Gomez...

The tempers flared...