Reeve was first confronted in the foyer by an angry Kevin Clarke, and then engaged in an awkward and lengthy handshake - and a rugged pat on the back - by David D'Amato in the theatre.
Both feature in Tickled, Farrier and Reeve's documentary which uncovers an alleged seedy side to a series of seemingly harmless tickling videos being posted online.
Their film, which has received rave reviews and has a 94 per cent approval rating on Rotten Tomatoes, debuted in US cinemas over the weekend, and the pair were there hosting separate Q&A sessions after select screenings.
Reeve told the Herald he arrived at the Nuart Theatre hours before his Q&A session was due to begin out of boredom, but quickly realised it would be a screening unlike any other.
"I was a bit bored. I showed up early. I was sitting there and I saw some guys who I recognised. They were minor players in the movie. Then I went outside and there was Kevin (Clarke), one of the big players. That was a surprise. At that point I knew something was going to happen," he says.
"Then I saw David (D'Amato) walk in. I thought, 'Wow, this is going to be something.' We scrambled so we caught everything on film. To the best of my knowledge he (D'Amato) has never seen the film before."
He and Farrier hadn't discussed the possibility that D'Amato would show up to a screening unannounced because they didn't believe it would happen.
"We would not have entertained it at all. If you were in his position, going there doesn't really make sense so we didn't expect it."
With Farrier hosting his own Q&A session in New York, Reeve was left to handle the situation on his own while his fimmaking buddy watched it go down on Facebook.
Reeve received plenty of praise from viewers for staying composed during his heated conversations with Clarke and D'Amato.
"The whole gist of our film is that we've found these people doing things that seem outlandish and unreasonable, and we want to take a rational look at it," he says.
"We see ourselves, and hope that other people see us, as being fairly rational and fair investigators who want to uncover and understand an unusual thing.
"It was important to me that I didn't lose my cool, and I let them say whatever it is they wanted to say, while I also got to say my piece as well."
And he's not worried about a series of legal threats made by D'Amato during their conversations.
"I think it was just an attempt to ... intimidate us, or make some sort of show. Until (the legal threats) materialise they're like so many other threats we have had that didn't amount to anything," he says.
"Once they do materialise we can assess them as whatever they are. Until then I'm not too worried."
But Reeve admits it's yet another twist in Tickled's strange journey into cinemas.
"After a while, words like 'insane,' 'crazy' and 'unbelievable' aren't strong enough any more."
