Exclusive: A documentary about the legendary Billy Preston that’s set to debut tonight at SXSW might not see the light of day.

“Instead of creating the film that they falsely described to Plaintiffs, Defendants White Horse Pictures, LLC, Homegrown Pictures, Inc. and Oyster Productions, LLC, by and through their principals and representatives Defendants Nigel Sinclair, Jeanne Elfant Festa, Stephanie Allain Bray, Paris C.K. Barclay and Cheo Hodari Coker, produced a film that is a salacious, posthumous ‘outing’ of Mr. Preston that centers on his sexuality – a deeply personal matter that Mr. Preston kept private until immediately before his untimely death – to the exclusion of many of the late musician’s notable accomplishments,” reads the fraud complaint filed today in Los Angeles Superior Court by Rock and Roll Hall of Famer Sam Moore of Sam & Dave, Preston Music Group, Ken Burke and others.

The Paris Barclay-directed documentary,...