"Game of Thrones" star Lena Headey says she's ferocious like her character Cersei in one particular circumstance: "When it comes to my child.”

The mother-of-one star tells More magazine she can't believe how lucky she was to land what has become the role of her lifetime on the HBO hit.

"Right now I’m having a very great moment, but it’s a moment," she said. "And I always think, OK, worst-case scenario: Could I survive in my car? Would this be OK? My friends call it disaster thinking. I like to think of it as realism.”

Headey, 41, has been through her share of ups and downs, including he recent split from musician Peter Loughran, and her fight with depression.

“I haven’t had a spell in a long time. I think some people’s brains are just wired that way if you’re a thinker," she explains. "People who never get anxious always amaze me. The world could be breaking up and they’re saying, ‘Everything’s fine!’ Getting older and having kids, you learn how to become less serious about it all.”

More On This...

But one thing she remains deadly serious about is her growing tattoo collection.

“I always want more. It’s a terrible thing. I’ll be outside a tattoo shop and hear the needle and think, I could just get a little one that nobody would see.”

Go to More ... for more!

Break Time: Guys, stop hitting on women at the gym