Niall Horan is incredibly organised, something that fans picked up on in 2016.
When they asked him on Twitter about it, he simply stated, "It's called OCD haha."
Fans wrote it off as a joke (which is something many people actually do when it comes to this mental disorder), however, it turns out Niall really does have Obsessive Compulsive Disorder. The disorder is "a common, chronic and long-lasting disorder in which a person has uncontrollable, reoccurring thoughts and behaviours that he or she feels the urge to repeat over and over."
Niall has opened up to German children’s magazine ZEIT LEO, admitting that, "I have mild obsessive compulsive disorder, that's what doctors call it.
"That is, I feel like I have to do things a certain way. For example, if I have a burger with chips on my plate, I always have to eat the chips first and only pick up the burger at the very end."
Niall explains that he has "other ticks in [his] life," which includes a specific ritual he does before he performs.
He explains, "I have one fixed sequence. I always have to sing in the same order, move and so on. And I’ll basically do everything immediately, otherwise I’ll get nervous quickly. That’s why in school I learned to start studying for tests very early. Otherwise I’d be afraid of the pressure."
The singer went on to explain that the ticks made it hard for him to relate to classmates when he was growing up.
"I live with them and they’re mine no matter what others think about it," he continues. "I’m just like — what the hell! Fortunately, I now have enough people around me who understand me."
Niall isn't the only celebrity to open up about their struggles with OCD. The likes of Daniel Radcliffe, Justin Timberlake and Lena Dunham have all spoken out about their battles in the past.
After his admission, fans flooded him with support.
If you, or anyone you know are suffering from mental illness, contact Beyond Blue at 1300 22 4636, or visit their site.
If you or someone you know needs help, you can speak confidentially to a trained counsellor 24 hours a day at headspace.org.au or Kids Helpline: 1800 55 1800.