AceShowbiz - Sara Sampaio suffers from hair-pulling disorder trichotillomania.

The Portuguese model is one of the world's most beautiful women, with her sultry looks landing her a pair of Victoria's Secret Angel wings, as well as campaigns and editorials for the likes of Vogue, Maxim and Dundas.

But opening up to fans in a series of Instagram Stories, Sara has admitted that she's secretly battling trichotillomania.

After a fan asked her how she maintains her brows in a spontaneous Q&A, the brunette star shared: "Well I try not to touch them, but unfortunately I suffer from trichotillomania and I pull them! (crying face) so I have lots of gaps in them. I just use (an) eyebrow pencil to fill out the gaps!"

The confession led to numerous followers who suffer from the same disorder getting in touch, so Sara explained in detail about the condition, which started when she was 15.

After telling her audience that trichotillomania is "an impulse control disorder" characterised by a long-term urge that results in the pulling of one's hair, the 27-year-old recalled how hers began with her eyelashes before she started touching her eyebrows.

Sara shared her story about having trichotillomania and spread a really kind message ♥️ pic.twitter.com/N9poDlGWCD

— Angel Sara Sampaio (@MyAngelSaraS) July 20, 2018

She added that she feels "lucky" as her eyebrows are strong and grow back quickly, though there are often lots of gaps.

"I'm not ashame(d) of it. It's a part of me (a "crazy" me) Hahahaha but it's who I am! So if you have it, don't be ashame(d) to talk about it and don't be ashame(d) of it!" she urged. "So always be kind to people, don't judge. This is a (psychological) disorder that people simply can't stop! But being understanding and kind goes a long way (sic)."