Defenders of the Earth - Necklace of Oros is a UK VHS released in 1991 by Video Gems.
Description[]
The necklace of Oros would give Ming his long-awaited wish of knowing the secret of gravity. Knowing that it is Jedda's birthday and, on that day, she gets to select a gift from the family jewels, Ming arranges through Gravitron that she select the necklace. This begins another splendid episode in which the forces of good and evil are colorfully depicted through luxurious landscapes and terrifying aliens.
Once Jedda selects the necklace she is fair game for Gravitron, an evil alien reptilian/humanoid. It is Mandrake who suspects some dirty deed is going on and hypnotizes her. Under hypnosis she reveals she reveals the power of the necklace – and Gravitron's role in it.