United Kingdom, Oct. 7 -- Charlie Hunnam feared he'd made a "horrible mistake" by agreeing to star in Monster: The Ed Gein Story.

The 45-year-old actor plays the titular murderer and grave robber in the third season of Netflix's anthology series but was concerned that playing such a dark role could be harmful for his career.

Speaking to Entertainment Weekly, Charlie recalled: "Once I said yes to this, I thought I'd made a horrible mistake.

"I started researching it, reading all the books about Ed Gein, and I fell into a full panic. I just thought there might be no coming back from this. This is so dark, to inhabit this character."

The Sons of Anarchy star explained how he was only calmed when he realised that showrunner Ian Brennan's ...