Hollywood Feud of the Day: Baldwin vs. Costner!

In an oil-filled world, one man has found himself on the short end of a slick business deal and his name's Stephen Baldwin

It is on!

Stephen Baldwin is looking to kick some Kevin Costner ass, filing a lawsuit today claiming the Robin Hood: Prince of Thieves star screwed Baldwin out of millions of dollars from Costner's oil-cleanup business.

Hollywood couldn't make this stuff up...

In the federal lawsuit filed Wednesday in New Orleans, the 44-year-old Usual Suspects star accuses Costner and his business partner of securities fraud and misrepresentation.

Baldwin says he had a 10 percent stake in the company, Ocean Therapy Solutions, which manufactured a centrifugal device to separate oil from water that Costner spent years developing.

Baldwin alleges he and a friend, Spyridon Contogouris, were "clandestinely, secretly and wrongfully" duped by Costner and partner Patrick Smith into believing there was no interest in the technology, leading to Baldwin and Contogouris to sell their shares.

Only later did Baldwin say he learned that the BP licensed the technology for $52 million to help clean up the Gulf Coast following last April's oil rig disaster.

No word how much he's asking for in damages, but given the percentage he gave up, we're guessing it's somewhere north of $5 million.

No doubt Baldwin could use the money. He filed for Chapter 11 bankruptcy a year and a half ago, owing more than $2.3 million to a bank and the IRS after defaulting on the mortgage on a New York residence.

Things got so bad, in fact, that fans set up a website to solicit donations.

Reps for Costner and Baldwin have declined to comment on the lawsuit.