The hat may be a joke — the sales sure aren't.

A New Jersey baseball cap maker that specializes in presidential election campaign gear says its most popular hat this cycle has been one about Donald Trump, according to an NJ.com report.

But it's not the hat you're thinking.

The "Make Donald Drumpf Again" cap plays off a gag about Trump that HBO funnyman John Oliver made last month on his show "Last Week Tonight," after learning that The Donald's ancestral family name was in fact Drumpf.