Gimme back my coat....

Dr Arnie Klein MJ's longtime dermatologist and friend has filed a claim against Michael Jackson's estate ... seems he wants his green jacket back.

Dr. Klein claims Michael borrowed a Gianfranco Ferre green jacket from him several months before he died , a jacket Klein claims is worth $10,000.

According to the claim, "The jacket has not been returned prior to death and has not been returned after death (although demand has been made)."

Klein is not asking for any money, but wants his blazer back.

Klein filed another claim against the Michael Jackson estate back in October -- for $48,522.89 for medical services.