New York may well be the city that never sleeps, but it also seemingly has the largest collections of loons per square mile than any other city. But only one eccentric character can claim to have appeared in over a 100 Hollywood films: Radioman.

In 1990, Radioman (real name Craig Castaldo), came across a film crew in the city that has trouble sleeping, shooting a film. He saw a man in a raincoat who looked a little down and out, like himself, and offered him a beer. The man turned out to be Bruce Willis in costume for his role on the film Bonfire of the Vanities. From that moment on, Radioman was hooked.

Since then, Radioman, along with his bicycle and trademark stereo around his neck, turns up, regular as clockwork, to all the location shoots in the city. And for the last twenty odd years, Hollywood's biggest stars have come to know and love Radioman, and expect him to show up when they're filming there.

This documentary goes some way in attempting to understand why Radioman does what he does (all his immediate family are gone, and he spent a number of years being homeless and an alcoholic on the streets of NYC), but ultimately resorts to stars such as Tom Hanks, Robin Williams and Josh Brolin saying nice things about him on screen.

Wow, It's not often you can get 'before' and 'after' at the same time!

Radioman believes that having met these actors many times over (and in many cases acted alongside them, albeit in a background acting capacity, making him a real life New York version of Extras character Andy Millman), that he has some kind of friendship with them. Although many show a genuine fondness for him, and are happy enough to name check him, the majority appear tolerate him in a respectful manner, more than anything else.

It's also quite eerie having Robin Williams talk about him, as he strikes an uncanny resemblance to the man himself; so much so that they wouldn't need to look far if they wanted to someone to play him in a big screen biopic.

There's no denying that Radioman is the perfect subject for a documentary like this; he is charming, affable, and has real passion for the movies, all wrapped up in genuine New Yorker attitude.

However, it would have been interesting to delve a little further into his personal life – there's no talk of any real friendships, romance or children, for instance. Nor is there any indication of how he sees the rest of his life panning out.

Still, Radioman is a fascinating account of one man's curious journey from background artist to leading man – albeit for one night only in his own documentary.