TMZ has confirmed Orlando Bloom will be called as a witness in the Burglar Bunch trial ... and he'll testify about the heist at his house.
Alexis Neiers is charged with one count of felony burglary ... for allegedly stealing two beaucoup expensive watches from Bloom's house -- which, along with some other items, were worth an estimated $500,000.
Interesting ... sources tell us Neiers turned down two plea deals from the L.A. County D.A. -- one for 1 year in county jail, and another for 6 months in jail. She's now rolling the dice and the stakes are 6 years in state prison.
Neiers' trial starts Monday.