A successful US comedian who crafted a public image as a spokesman for the "Millennial" generation is 20 years older than he claims, it has been revealed.

Comedian Dan Nainan has scored personal endorsements from a range of respected public figures, including Barack Obama.

He travels the globe taking high-paying stand-up gigs at corporate events, and makes frequent media appearances providing a Millennial voice in articles about everything from young Trump voters to youth attitudes to porn.

There's just one problem: Nainan is 55 years old.

Advertisement

Nainan's stand-up act usually focuses on jokes about his mixed-race heritage rather than his age, but it was his more recent reinvention as the go-to Millennial for media outlets that raised alarm bells.

A November AP profile of young undecided voters in which he was interviewed left some readers puzzled, illustrated as it was with a feature-sized picture of Nainan looking far older than his claimed 35 years.

But it seems a recent Forbes profile on the comic was to be his unravelling.

The piece cast Nainan as an impressive comic Wunderkind, leaving behind his high-paying tech job to follow his natural passion for stand-up - the textbook example of a career-hopping Millennial entirely reinventing themselves, all before middle age.

After the piece was published, Daily Beast reporter Dan Collins started digging and, before too long, found many holes in Nainan's backstory.

Through the years, Nainan had frequently recounted the story of his start in comedy: he was working as a senior engineer at Intel in New York during 9/11. He watched the attacks unfold in real time from his corner office and decided there and then that he needed to throw in the job he'd worked so hard for and instead pursue his love of stand-up comedy.

According to Nainan's timeline of events, he would have been just 19 or 20 at the time.

The Daily Beast also uncovered hard proof - in the form of court papers, speeding tickets and other official documents - that showed "35-year-old" Nainan's real birthdate to be May, 1961.

So how was Nainan able to fool so many people for so long?

Well, it seems many in comedy circles knew he was far older than he claimed - but Dainan is notorious for badgering comics who speak out against him with harassment and intimidatory tactics.

One such comedian, Joe Robinson, told the Daily Beast he received more than 300 angry emails from Nainan after he spoke poorly of him on a podcast.

Others received similar email harassment, ranging from the petty - endless boasts that Nainan was booking more prestigious gigs than them - to the disturbing (challenging his comic foes to fight him to the death).

"I feel bad, but it also feels like there's some sort of danger to it. Other than speaking to you, I, for the most part, have abstained from talking about it. It's 85 per cent because I don't want to bother him," comedian J-L Cauvin told the Daily Beast.

Confronted by the Beast's Ben Collins with evidence of his own deception, Nainan initially declined to comment, insisting that "I just don't think there's any benefit to me commenting. It is what it is."

Given the opportunity to clear up once and for all whether he's 35 or 55, Nainan insisted it was the former.

"I'm 35," he told theDaily Beast. "The mistake is in my birth record."

Right now, it seems he's scored every comic's greatest wish - the whole world is laughing at Dan Nainan.