The British star portrays scheming royal Cersei Lannister in the hit fantasy series, and the season five finale last year (15) featured her character stripped naked by religious leaders, and forced to take a walk of shame to atone for her incestuous affair with her twin brother.

The 42-year-old was pregnant at the time of the shoot in Croatia and opted to have another actress stand in for her, so producers used computer-generated imagery (CGI) to superimpose Headey's head onto Rebecca Van Cleave's naked figure. That didn't sit well with some viewers, who attacked Headey for refusing to disrobe and film the scene herself.

"(There were some) really great (reactions)," she told Entertainment Weekly, 'but some people thought I was less of an actress because I didn't get my t**s out."

Headey went on to explain she didn't feel she would be in the right place emotionally to pull off the lengthy shoot properly, and so she stepped aside.

She continued, "It was really a bit shocking. I've done nudity. I'm not averse to it. But I know I'm a very emotional actor and I get really driven by that. In order to do my job, I allow myself to be really vulnerable. I don't know any other way to do my job. Things really affect me.

"The thought of being naked for three days and trying to contain her (Cersei) in the way she would be, I think I would feel very angry... and wonderful Rebecca was able to contain herself and be naked. She found it very difficult, obviously. It's not a natural thing to do."

Headey admitted her role as a mum also played into her decision.

"I film every year and I have kids and they know me now and (being naked in the scene) was just too much on top of that," she added. "So yeah, people that get it thought it was great. I didn't phone it in; I was actually there for three days with Rebecca."

Van Cleave previously defended Headey over her decision not to shoot the controversial scene, insisting fans should only be concerned about the final cut.

"It should all be about the finished product, not about whose body was where and and whose head was where," she stated.