Robbie Williams has opened up about his struggles with "inside Tourette syndrome" and intrusive thoughts.

In a recent interview for the I'm ADHD! No You're Not podcast, the Angels hitmaker candidly discussed his Attention-Deficit/Hyperactivity Disorder (ADHD) diagnosis.

Robbie also revealed that he believes he has a form of Tourette syndrome, a neurodevelopmental disorder characterised by multiple movement or vocal tics.

"I've just realised that I have Tourette's, but (the tics) don't come out," he told co-hosts Dr Mine Conkbayir and Paul Whitehouse. "They are intrusive thoughts that happen. I was just walking down the road the other day, and I realised that these intrusive thoughts are inside Tourette's. Not only that, you would think that a stadium full of people professing their love to you would work (as a distraction), but whatever it is, inside me, (I) cannot hear it. I cannot take it in."

Robbie went on to recall how he recently took an online test to see if he was autistic.

But while the British singer has "autistic traits", he has never been formally diagnosed with autism spectrum disorder (ASD), which tends to be typified by differences or difficulties in social communication and interaction.

"It turns out I'm not (autistic), but I've got autistic traits. And it's around, social stuff, it's about interaction," the 51-year-old explained, adding that he would like a diagnosis because it would give him an "understanding of why I feel so uncomfortable in my skin".

"When I'm in bed, that's my comfort zone. Anywhere outside of that bed is my discomfort zone," he added. "It's getting better. It was awful, horrendous through my 20s, bad through my 30s, my 40s started to get better and I'm on an upward curve, but I'm still uncomfortable in my skin. Much like I have sought out medication to fix it, I'm constantly still looking for the reason and the whys."