LOS ANGELES (AFP) - Veteran US comedian Jerry Seinfeld says he thinks he is on the autism spectrum, describing it as an "alternate mindset."

"I think, on a very drawn-out scale, I think I'm on the spectrum," Seinfeld told NBC's "Nightly News" late Thursday.

The multi-millionaire actor - famous for his semi-autobiographical 1990s sitcom Seinfeld - said he was "never paying attention to the right things."

"Basic social engagement is really a struggle. I'm very literal. When people talk to me and they use expressions, sometimes I don't know what they're saying," Seinfeld explained.

"But I don't see it as dysfunctional. I just think of it as an alternate mindset."

The cause of autism, a complex neurodevelopmental disorder characterised by social withdrawal, is thought to be roughly split between genetic and environmental factors, according to experts.