'This Is It' Producer -- Star Witness in MJ Prelim

1/4/2011 11:30 AM PST

Kenny Ortega, Producer of 'This is It" tour will be Star Witness in Michael Jackson Conrad Murray Manslaughter Preliminary Hearing

Michael Jackson's producer/director for the "This Is It" tour will be a star witness for the prosecution in Dr. Conrad Murray's preliminary hearing which begins today  ... sources tell TMZ.

Our sources tell us ... Kenny Ortega will testify that on June 19, 2009 -- a week before MJ died -- Michael complained he was cold, had the shakes and was unable to perform ... so the rehearsal was canceled.

The next day -- June 20 -- an emergency meeting was held at Michael's home.  Kenny Ortega, several big wigs from AEG, Michael, and Dr. Conrad Murray were present.  We're told the meeting was "intense, loud and argumentative."  Kenny read Michael the riot act, imploring him to take better care of himself because the tour was imminent.  

Ortega will testify, during the meeting, Dr. Murray said some "terrible things," showing a lack of concern and respect for Michael.  Our sources would not reveal specifics, but we're told it's "damaging" to Murray.

Sources say rehearsals were canceled on June 21 and 22 so Michael could regain his strength. Ortega will testify ... when rehearsals resumed on June 23 and 24 -- the day before Jackson died -- Michael did a complete turnaround, wowing the backup dancers and others present with his moves and singing.

Ortega's testimony is important, because prosecutors will argue MJ was fine before Murray began pumping him with drugs the day he died.