Scott Nathan filed papers in April (10) alleging he was hired to take shots of the Mean Girls actress for her clothing label 6126 in return for a one per cent interest in the business.
But he claims he has received no payment, and is seeking unspecified damages. He is also suing Universal Music Group for copyright infringement and breach of contract, alleging one of his photographs was used on the cover of Lohan's single Bossy.
A settlement conference between Lohan's lawyers and Nathan's legal team is scheduled at a Los Angeles court on Tuesday - and Lohan is expected to attend the hearing, according to EOnline.
Nathan's lawyer Phillip Nevinny tells the website, ""I think this is an example of yet another corporate entity running over the rights of an artist. It is just wrong on every level. We are confident of our position and the truth will come out in trial.""
Lohan is currently undergoing a three-month court-ordered stay at California's Betty Ford Clinic after failing two drug tests, and is expected to remain in the facility until next year (11).