Amanda Seyfried is one of the most charismatic actresses out there, but behind closed doors many don't know that she is facing a constant battle.
The 30-year-old suffers from Obsessive Compulsive Disorder (OCD) and tells Allure magazine that she has been medicated for over a decade.
If you have OCD, you'll usually experience frequent obsessive thoughts and compulsive behaviours.
An obsession is an unwanted and unpleasant thought, image or urge that repeatedly enters your mind, causing feelings of anxiety, disgust or unease.
A compulsion is a repetitive behaviour or mental act that you feel you need to carry out to try to temporarily relieve the unpleasant feelings brought on by the obsessive thought.
Amanda said: "I'm on Lexapro, and I'll never get off it.
"I've been on it since I was 19, so 11 years.
"I'm on the lowest dose. I don't see the point of getting off it.
"Whether it's a placebo or not, I don't want to risk it. And what are you fighting against?
"Just the stigma of using the tool?
"A mental illness is a thing that people cast in a different category [from other illnesses], but I don't think it is.
"It should be taken as seriously as anything else."
Sticking by the actress every step of the way is fiance Thomas Sadoski, who first met Amanda on the set of the play The Way We Get By.
Amanda also discussed the ignorance that surrounds mental health issues nowadays, she insists that people shouldn't have to "prove" that they are suffering.
She said: "You don't see the mental illness: It's not a mass; it's not a cyst. But it's there.
"Why do you need to prove it? If you can treat it, you treat it."
The Mamma Mia star also confessed that first, she thought she had a brain tumour.
"I had pretty bad health anxiety that came from my OCD and thought I had a tumour in my brain.
"I had an MRI, and the neurologist referred me to a psychiatrist.
"As I get older, the compulsive thoughts and fears have diminished a lot. Knowing that a lot of my fears are not reality-based really helps."