Their first screenplay together won them an Oscar (The Descendants), while their latest movie together The Way Way Back is winning plaudits and critical acclaim from all around.
So we sat down with the sickeningly multi-talented actor/writer/director duo Jim Rash and Nat Faxon to get some script writing tips - including advice they'd give their younger selves, how their acting experience informs their writing, and - most importantly - how they settle co-writing disagreements.
It involves slapping.
The Way Way Back is in UK cinemas from 28 August 2013.
Love the look of The Way Way Back? Let us know below...