It’s ad execs all the way down: Twitter is making a documentary about itself for the benefit of the advertising crowd gathered at the Cannes film festival.

A later cut of the same documentary will show ad execs at Cannes watching the documentary. Movie magic!

The documentary, which will feature Sir Patrick Stewart, Aaron Paul, Al Roker, and some top ad and media execs, will try to make the point that Twitter has brought a sense immediacy and openness to digital advertising.

Twitter plans to film the reactions of ad execs while they watch the documentary at the Cannes film festival in France. I’m not sure why anybody would want to watch that kind of navel-gazing; but then, I don’t live in the highly prestigious world of online advertising.

One part of the documentary shows a team of marketing people trying to craft clever tweets during the Super Bowl. In another part of of the documentary, a TV producer demonstrates how he uses Twitter to do his job.

This will be Twitter’s third year at Cannes, which holds a festival and awards show for advertisers every year. Twitter gets almost all its revenues from sales of sponsored tweets.

Advertisers are still warming up to the idea of placements on Twitter and are trying to understand the real effects on brand promotion.

Case in point: Omnicom Media Group recently signed a $230 million deal to place ads through Twitter’s ad network, MoPub, over the next two years.

However, Facebook still gets the lion’s share of interactive ad dollars spent on social platforms.