Margot Robbie gave Will Smith swimming lessons.
The 'Focus' actress was so shocked her co-star was unable to swim that she offered to teach him whilst they were on set.
When asked what the most surprising thing she found out about Will was, she said: "This was surprising for me because I'm Australian - he doesn't know how to swim. In Australia, I don't know anyone who doesn't know how to swim; you just grow up in the water - you learn before you can walk sort of thing.
"So I was like, 'Well this is crazy. You're missing out on so many water-sports and diving.' And so my mum is in Argentina visiting and we're like, 'Right you're getting in the pool right now and we're gonna teach you how to swim.'"
And whilst their efforts to turn Will into a water lover were initially despised by the 46-year-old actor, he has since taken lessons from an Olympic swimmer.
She added: "And he was hating it; he was like, 'I don't want to do this anymore.'
"Anyway now since then, he's gone off and apparently learnt from an Olympic swimmer because that's the way Will does it."
Meanwhile, the 24-year-old actress also admitted she thought she had "no chance" of securing her part in the crime drama after Will was given the leading role.
Speaking on US daytime show The Talk, she said: "I wanted to work with the directors and then Will was onboard and then I thought, 'Well now I've got no chance of the role because no one's ever gonna buy me and Will as a couple. No one's ever going to be like, 'Yeah, they look great together.'
"I didn't think I was going to get the role, or had a chance at it, but as it turns out we got into the room and we got on like a house on fire."