Costner is being sued by Baldwin, along with another plaintiff, seeking unspecified civil damages. Patrick Smith, a business associate of Costner's, and Pacific West Resources, a California company in which they are officers, are also named as defendants in the lawsuit, The (New Orleans) Times-Picayune reported.
U.S. District Judge Martin Feldman says both Baldwin and Costner must appear each day at the trial, WWL-TV, New Orleans, reported.
Baldwin and fellow plaintiff Spyridon Contogouris were minority stockholders in Ocean Therapy Solutions, which Costner formed to market a centrifugal device that separates oil from water.
The plaintiffs allege Costner failed to tell them about a meeting in 2010 in which the British oil producer BP agreed to make an $18 million deposit on an order for 32 of the devices that was valued at an estimated $52 million.
Baldwin says he and Contogouris, unaware of the meeting, sold their their shares in Ocean Therapy Solutions for $500,000 and $1.4 million, respectively, missing out on their share of $38 million in profits from the BP deal.