Arnold Schwarzenegger has added his voice to the outcry over the hunting death of a protected lion named Cecil earlier this month in Zimbabwe.

The action star and former governor of California said, "Stop killing big cats," in one post.

Schwarzenegger also tweeted the Instagram posts to his 3.46 million followers as part of National Geographic's fundraising drive raising money to protect big cats, the Telegraph reported.

>> Read more trending stories  

Walter James Palmer paid nearly $50,000 to shoot and kill a lion in the African country. It turned out the lion he shot with an arrow was Cecil, who was protected and part of an Oxford University research project.

Palmer is in hiding, but could be extradited to face charges, The Associated Press is reporting.

Palmer said he relied on his guides to make sure the hunt was legal.

The two guides have been arrested for the illegal hunt.

Cecil was baited from a protected wildlife park and shot, but didn't die immediately. He was found wounded about 40 hours later and killed. He was then skinned and beheaded, The Associated Press reported.