Lewis Capaldi says that before he was diagnosed with Tourette's syndrome he feared he was "dying" and had a degenerative disease.
The 25-year-old singer-songwriter went public with his condition last week on social media.
Tourette's syndrome causes a person to make involuntary sounds and movements called tics, according to the NHS website.
The Scottish star said his diagnosis "made a lot of sense", adding: "I raise my eyebrows quite a lot. I do this shoulder thing. I take these deep breaths every now and then.
"I thought I was dying because I am a hypochondriac, so I thought I had some degenerative disease. But I don't, so good news on that front."
In an Instagram Live last week following his diagnosis a few months ago, Capaldi said he received botox treatment in his shoulder to help control his tics.
On Tuesday, he told presenter Lorraine Kelly on ITV: "I got told like seven months ago or something like that, really recently.
"It made a lot of sense. To me, I am quite a jittery individual. A lot of people think I am on drugs when they meet me."
More than 300,000 people in the UK are estimated to have Tourette's - an inherited neurological condition.
Asked about the public reaction to him talking openly about his diagnosis, the Glasgow-born musician said: "People have reached out and they have said that I am an ambassador, which was great. So there you go, I have got a new title this week as well."
The singer said that "sometimes you feel you are alone in these things, and it is nice to just see that you are not so isolated in all this stuff".
He added: "It has been a bit of an eye-opener, but it is nice."
Capaldi also discussed the release his song Forget Me - his first new music in three years - the day after the Queen died last Thursday, saying: "Not a great week to release a single... Let me tell you that."
Capaldi on monarch's passing
Reflecting on the royal's death, he added: "It is a sad thing. And then you see the family all sad and it just reminds you as well that people in your own family have gone."
The singer's 2019 debut offering, Divinely Uninspired To A Hellish Extent, became the biggest album of the year, according to the Official Charts Company. His second album is expected soon.
The NHS website says people with Tourette's syndrome have a combination of physical and vocal tics.
Examples of physical tics include blinking, eye rolling, grimacing, shoulder shrugging, jerking of the head or limbs, jumping, twirling, and touching objects and other people.
Examples of vocal tics include grunting, throat clearing, whistling, coughing, tongue clicking, animal sounds, saying random words and phrases, repeating a sound, word or phrase, and swearing.