The singer fronted the project for exercise company Speedfit, but she didn't like the finished result and filed legal papers to keep the DVD from being sold.
In a defiant letter to Simpson's lawyers, obtained by WENN, the new owner, Ed Meyer, writes, "After much due diligence, I have purchased rights to distribute the as yet unreleased Jessica Simpson Exercise Video from Speedfit.
"While your client Jessica Simpson believes that she has a valid New York court order preventing such a contract, she actually does not."
Meyer insists his contract with Speedfit is "valid", and he has threatened Simpson with legal action if she insists on moving forward with "any tortuous interference or restraint of trade".
The producer plans to re-edit the fitness film, which was shot in 2005, and release it. Simpson won an arbitration ruling to keep the exercise video from being distributed – a huge hurdle for Meyer.
She also won a ruling barring Speedfit from using her name and likeness to promote the video.