How to make a Judd Apatow movie

1. Assemble the essential ingredients: (clockwise from top left) Seth Rogen, Jason Segel, Leslie Mann, Paul Rudd Photograph: Universal/Everett/Rex Features

2. Divide the male and female ingredients into strictly separate piles, ideally into separate houses with gender-divided decor Photograph: Sportsphoto Ltd./Allstar/Universal

3. Add some marijuana to the men (Knocked Up, Pineapple Express), and top with the funniest lines (Anchorman) and worst personal hygiene (Knocked Up). Sprinkle the women with maturity and just a hint of uptightness (all) Photograph: Sipa Press/Rex Features

4. Mix thoroughly, wait for one of the men to react in an unexpected way, like fall in love Photograph: Allstar/Universal/Sportsphoto Ltd./Allstar

5. Throw in at least one physical comedy set-piece, such as a very painful male chest wax (40 Year Old Virgin), psychadelic delusions (Knocked Up, Talladega Nights) or general male nudity (Forgetting Sarah Marshall) Photograph: Universal

6. Bake thoroughly until a golden crisp of domestic happiness has topped the dish Photograph: Allstar/UNIVERSAL/Sportsphoto Ltd./Allstar