Larry David's upcoming mystery movie has left the confines of Fox Searchlight and found a new home at a familiar location: HBO, the home to David's Emmy-winning series 'Curb Your Enthusiasm.' But what exactly is this movie?

David's return to filmmaking (he wrote the poorly received 1998 comedy 'Sour Grapes') was set up at Fox Searchlight when along came HBO who, as the old Hollywood maxim goes, wanted to stay in the Larry David business. According to the Los Angeles Times, HBO offered David and his director Greg Mottola ('Adventureland') a sizable budget increase over what Searchlight was willing to offer and now instead of hitting theaters, David's film will instead premiere on the cable channel.

Set to star David, Jon Hamm and Michael Keaton the movie is...well, we don't really know. No one is talking about specifics but it's based on an idea David himself concocted and wrote with his former 'Seinfeld' writers Alec Berg, David Mandel and Michael Schaffer (who also worked recently on Sacha Baron Cohen's 'The Dictator').

Despite the fact that there will be a script, the movie is expected to be highly improvised, very much like 'Curb Your Enthusiasm.'

What's a likely possibility is that HBO's offer for a larger budget for this film may have included the condition that David return for another season of 'Curb Your Enthusiasm,' a matter on which David has been waffling for the past few months.