Lena Heady Game of Thrones

Lena Heady

photo: HBO

Mental illnesses are indiscriminate. They can strike anybody at any time. Actress Lena Headey, who currently stars as Cersei Lannister on "Game of Thrones," drove this point home in a candid Twitter thread about anxiety and depression.

On Thursday, a Twitter user asked Headey if she ever struggles with insecurity.

Surprisingly, the 43-year-old responded to the tweeter — and dropped some tools she's used to cope with anxiety and depression.

She didn't stop with that singular answer. Instead, Headey's fielded questions about mental illness from multiple fans.

Headey then explained what she believes fuels anxiety and depression.

There's a real reason why Headey's vulnerability is resonating with thousands of people on Twitter.

Anxiety and depression are two of the leading mental illnesses in the US. Anxiety disorders are the most common mental illness in America, according to the National Institute of Mental Health. About 40 million Americans, or 18% of the US population, has an anxiety disorder.

In 2014, the Anxiety and Depression Association of America found that 15.7 million adults in the US had a major depressive episode. Between 3% and 5% of adults have chronic depression.

Celebrities, like Headey, publicly sharing their own struggles helps to normalize mental illnesses and reduce the stigma associated with them.

Headey ended her Twitter thread by offering a few nuggets of wisdom to other people battling anxiety and depression.

A little encouragement from a Lannister surely goes a long way.