Orlando Bloom threw a punch at Justin Bieber early Wednesday morning in Ibiza ... and Justin fled the restaurant -- this according to 2 eyewitnesses.
The eyewitnesses tell TMZ ... Orlando was in Cipriani restaurant which was packed with celebs, including Paris Hilton, and Diddy.
You don't see Orlando swing, but the eyewitnesses tell us that's exactly what happened. We're told Justin ducked the punch.
See this story on www.tmz.com