Lenny has been tipped to play the Motown star in an upcoming film which is said to focus on Marvin's life in the '80s and his battle with drug abuse and depression.
Son Marvin III is said to be against the making of the movie, which has the working title Sexual Healing.
"The producers and directors of this film are very wrong and shameful ... [They''re] trying to do a film about a low period in his life. They don''t even know the whole story," he apparently fumed to TMZ.
Marvin III claims he and 48-year-old Lenny are childhood friends, who even went to the same school.
He wants to talk to his pal about the decision to take on the role, claiming other family members are meeting with lawyers to put a halt on production.
"[I want to] talk to him about why he would do this," he explained. "I would hope [Lenny] doesn''t have any idea that we are against this film being done."
TMZ reports they failed to reach Lenny for comment.
Gaye passed away 1984, after he was shot by his own father.