After languishing in development hell for many years, there was a time not so long ago where it seemed that the Merc with a Mouth would never get a blockbuster movie of his very own.
However, in July 2014, animated test footage leaked online showing what a Deadpool movie could look like, with Reynolds himself lending his voice to the short clip.
The video quickly went viral, demonstrating massive interest in the character and convincing Fox to finally ramp up production on his long-gestating solo feature.
In the years since, there has been much speculation over who exactly was responsible for the leak, with both Reynolds and director Tim Miller among the prime suspects.
Exactly six years on, Reynolds shared a video to his Twitter page featuring a special Deadpool edition of the Unsolved Mysteries opening sequence, joking that the reason for Deadpool 3's delay is that he's "still trying to solve this".
Interspersed among footage of the first Deadpool movie, we see a pinboard featuring pictures, article cut outs and bright red scribblings, one of which reads: "Who leaked? 70% sure not me."
Possible culprits that Reynolds has picked out include his own wife Blake Lively, his X-Men co-star Hugh Jackman, Deadpool creator Rob Liefeld and Betty White.
Previously, during an interview on The Tonight Show with Jimmy Fallon, Reynolds had suggested that the leak could only have been done by one of four people: himself, director Miller, or screenwriters Rhett Reese and Paul Wernick.
If he's looking for answers, it's understandable that he would turn to the Unsolved Mysteries format, given its impressive history of settling cold cases.
The producers of the series have said that several useful tips have come in since the latest episodes aired, with plans to keep fans updated on all the latest developments.