If you're going to be spending a day filming lengthy sex montages with your co-star, it helps not to take yourself too seriously.
Luckily, as you can tell from their appearance on The Graham Norton Show, Ben Affleck and Sienna Miller clearly know how to have a laugh together.
"Sometimes I like to just go over and over again without cutting and interrupting the flow..." says Affleck in the clip above, when asked about the copious love scenes he wrote into new film Live by Night.
"Careful with your words, Ben," interrupts Miller.
