Sen. Rand Paul (R-Kentucky) Reuters/Jonathan Ernst US Sen. Rand Paul (R-Kentucky) is reportedly raising presidential campaign cash in an unusual place on Tuesday: the Cannabis Business Summit.

According to an invitation obtained by Yahoo News earlier in the month, Paul is holding a "private briefing" with his campaign donors while in town for the marijuana industry event in Denver, Colorado. Other outlets, including The New York Times, also confirmed the event.

However, the fundraiser is not going to be at the event itself.

"Senator Paul is not speaking at the Cannabis Business summit, our campaign is hosting a fundraiser which is open to those wishing to support our campaign," the Paul campaign told Business Insider. "The fundraiser is organized by us and not by anyone else."

Colorado famously legalized the recreational use of marijuana last year.

A National Cannabis Industry Association email reportedly declared, "Major Republican Presidential Contender at Cannabis Business Summit!"

“Never before has a major-party presidential candidate held a reception at a cannabis industry event, and NCIA is proud to host Senator Paul," the message said.

The group's deputy director, Taylor West, further told The Denver Post that Paul's fundraiser will be truly historic.

"Its the first event that we know of that a presidential candidate will be involved in the industry," West said. "He's kind of in a class of his own."

Paul, who has been aligned with several libertarian causes, has pushed several legislative drug reforms in the Senate, including reducing the sentencing disparity between crack and powdered cocaine, and making sure that food products containing drugs are "weighed fairly" by authorities.

He's also been spotted wearing a hemp blazer.

Clarification 2:10 p.m. to note the location of the Paul event.