A group of African elephants at Chimelong national center in Qingyuan, Guangdong Province. [Photo by Qiu Quanlin /chinadaily.com.cn]

Producing genuine tears on demand is one of the hardest parts of my job as an actress. Acting teachers will tell you that in order to cry on screen you need to summon up something personal－a fear, an inner secret, a sad experience－that taps into your deepest emotions.

This may sound strange, but the inner secret I use when I need to cry during a movie scene is the image of an elephant. It's an image that haunts me, an image that will remain in my heart and mind for as long as I live.

Two years ago I visited Samburu National Reserve, a wildlife park in Kenya. There, on a guided walk through the bush, I saw my first dead elephant. Poachers had hunted down this magnificent animal before piercing her tough hide with poisoned spears. As if she already knew her fate, the elephant had walked through the bush, the toxins coursing through her veins, until she found a quiet place to lie down. She chose to die in the cool shade of an acacia tree.

And that's where her body was when I saw her, lying in the dusty red soil, her face hacked off with machetes so that her killers could wrench the tusks from her skull. Around her dead body were the small footprints of a baby elephant; her child now left to fend for itself without the protection of its mother.

That moment, the sight of the dead mother and her mutilated body lying under the shade of the tree, changed something inside me. It made me sick in the pit of my stomach. I remember crying for her as I thought about the cruelty and senselessness that had led to her death. It made me angry, too: she died so that someone living thousands of miles away could buy a bracelet made from ivory, or some other trinket they could show off to their friends and neighbors, oblivious to the blood, sorrow and brutality that made these trivial objects possible.

But her death also fired me up. I stepped from the shade of that acacia tree knowing that to prevent the death of more elephants like her I would have to double my efforts to stop the illegal trade in ivory, which is fuelling so much misery in Africa.