Don Jon is a movie all about chemistry.
And there's no better or sexier immediate spark than that between 'buds-in-real-life' Joseph Gordon-Levitt and Scarlett Johansson.
While they sizzle on-screen, the pairing went far deeper than on-screen acting, with Johansson giving JGL invaluable feedback on his script, and helping mould the plot as a whole.
Watch JGL explain Johansson's background work in our video below.
Don Jon is in UK cinemas from 15 November 2013.