The 49-year-old actor opened up about his condition on Instagram Tuesday, said he received a formal diagnosis of autism a year ago, admitting that the news was "a shock but not a surprise".

"This isn't something I'd change," he added.

"No. I get – got – immediately being autistic is central to who I am. To everything, I've achieved/articulated... I also want to say to the many (many) people who consciously or unconsciously gave me that extra bit of grace + space over the years, allowed me to move thru the world in a way that made sense to me whether or not it made sense to them... thank you (sic)," Miller wrote alongside a blank white square.

Autism, or autism spectrum disorder (ASD), refers to a broad range of conditions characterised by challenges with social skills, repetitive behaviors, speech and nonverbal communication The actor, a graduate from Princeton University, said that he will now be "re-examining 5 decades of lived experience thru a new lens (sic)"