The documentary will hit TV screens in America this coming weekend (17-18Oct15) and Hedren and her Roar Foundation partners at the Shambala Reserve in California want fans to watch - even though the footage will leave many shaken.

In a note to fans, she writes, "If you haven't seen Blood Lions on MSNBC, it will air on Saturday and Sunday... Be warned that it contains graphic footage of the inhumane treatment and killing of lions on lion farms and canned hunts in South Africa.

"It is all about huge amounts of money, and psychopaths who have no sense of conscience or remorse. THE KILLING OF WILD ANIMALS IS A HUGE FINANCIAL AND EMOTIONAL SPORT!!!!!! This documentary will make you angry and sick to your stomach. DO SOMETHING TO STOP THIS ATROCITY FROM HAPPENING!!!! It is a hugely profitable, bloody business in South Africa!!!"

The Birds star adds, "INUNDATE THIS SOUTH AFRICAN PRESIDENT WITH YOUR DEMANDS TO STOP THE BREEDING OF LIONS TO BE SLAUGHTERED TO BECOME A HEAD ON THE WALL OR A RUG TO BE STEPPED UPON."

Attached to the missive, the actress also sends out President Zuma's email address and that of his chief director, as well as her telephone number.

Hedren's call for action comes just days after American dentist James Walter Palmer was cleared of any wrongdoing after shooting and killing a protected lion, called Cecil, in Zimbabwe.

The nation's officials are no longer calling for Palmer's extradition, and he's now free to return to Zimbabwe as a "tourist". Lawmakers have ruled he did not break any hunting laws by killing Cecil during a bow hunt in western Zimbabwe this past summer (15).