Kelly Reilly is "very introverted"

She told the BBC: "I'm very introverted. I don't have any dreams of vengeance in my life.

"There's something really exciting about playing her. I feel like I'm on an adrenaline rush for four months while I play her, and when I'm finished I'm like, I now have to go back to my quiet, boring life. And I'm very grateful for my quiet, boring life after I've played her.

"But by the time every summer comes around where I'm sort of gearing up again and the scripts start coming in, I get excited again to meet her.

"I'm very aware of the gift of her as a character, but I lock her up in a padlocked box for six months of the year."

Kelly's on-screen character has developed a big fan following, and the actress feels she's "penetrated a zeitgeist in women specifically".

Kelly explained: "I think it is that unencumbered kind of freedom that she moves through the world with. She is not afraid of dying, she is not afraid of losing.

"There is a scene in season two where she is being attacked by a man who is in the process of raping her and is about to kill her and she is covered in blood.

"She will not be a victim to him. And I think for women and for me, I love that. She is fierce."

Despite this, Kelly doesn't know what a happening ending would look like for Beth.

She said: "I would like something cathartic, potentially. I would hate to leave her out in the wilderness. But I don't know if happiness is something any of these characters strive for.

"They strive to protect, they strive to kill, they strive to be killed. These are not looking for peaceful lives."