NUTSHELL: Justin Bieber allegedly said something to Orlando Bloom about sleeping with Miranda Kerr (Orlando's ex-wife) and Orlando took a swing at Justin but was blocked by Justin's body guard.  After the incident, Justin briefly posted a picture of Miranda Kerr, took the picture down, then posted a picture of Orlando Bloom shedding a tear (see below... the picture is from a Broadway play Orlando attended)

Here's the FULL version of the details on this ridiculousness:

This story just keeps getting stranger.  Reports came though that Justin Bieber pushed Orlando Bloom at a restaurant in Spain and started a fight between the two.  THEN, reports came though that Justin tried to shake hands with Orlando, Orlando rebuffed Justin and things got physical.

NOW.... The woman who filmed the chaos at a restaurant in Ibiza, Spain earlier this week says Justin was DEFINITELY the instigator. She says he came in and saw Orlando sitting at a table with several people, including LEONARDO DICAPRIO.

And he said something that was, quote, "aimed at Orlando, who then jumped onto a sofa to try and get at Justin." ...sources at TMZ say that Justin made a crack at Orlando about Justin sleeping with Orlando's ex-wife, Miranda Kerr... while Orlando and Miranda were still married. 

The woman claims there were TWO moments when things got violent, and Leo was among many in the restaurant who were cheering Orlando on.

LINDSAY LOHAN was there, too, and she tried to play peacemaker . . . quote, "She tried to get Bieber a little bit calm when he went away to the exit but he was like, 'I don't want to speak to anyone.'"

Here's the Instagram Justin posted after the incident.