I don't usually review things negatively unless they are really bad (Twilight, Imma lookin' at chew) but this film really does fit this bracket, as well as being (at time of writing) the best part of twenty quid (ouch!).
One of the things that is most misleading is that David Tennant is given star billing in it. While his scenes are some of the few memorable moments of the movie, they are a tiny proportion of the whole, and certainly the only reason he's even listed as one of the top three is because of his popularity. Don't be fooled, if you're a Tennant fan, into thinking this is an undiscovered gem, because it ain't!
Even ignoring this totally, oh my goodness, it's just not a funny movie, nor an interesting one. I was bored by Dreyfus' character almost from the start and only doggedly reached the end of the movie because I thought it would surely liven up at some point. It definitely has some (rather acerbic) comments to make about the film industry, but witty? Hmmm. Nope. Too heavy and pointed and not nearly funny enough to be 'witty'.
Really and truly, this is one to rent, and even then only to rent if you really have run out of choices and have some strange masochistic need to watch a really dull movie. Boring, annoying characters, and a script the writers and director probably thought was hysterical. Maybe you need to be in the film industry, or maybe you just needed to be there, but how this pile of dreck got to be released on DVD when there are some classics out there that have never even been rebroadcast is utterly beyond me.
In short: Do not bother. This is 90 minutes of my life I'm never getting back; take my word for it, the movie does not get better if you stick with it.