AceShowbiz - Eddie Redmayne and Katherine Waterston needed regular pick-me-ups to get through gruelling shoots on the set of the new Fantastic Beasts: The Crimes of Grindelwald.

The actress turned to handfuls of gummy bears when her energy was flagging, while her castmate guzzled coffee.

Katherine reveals there was a particularly "magical" assistant on set, who seemed to know exactly when to dish out the treats.

"There was this PA who seemed to have the magical ability to deliver a dose of Gummy bears to the little holding area for the actors at the moment in the day right when I started to flag," she tells BuzzFeed. "It seemed as if by magic they would appear. I often wouldn't even see him do it.

"I would just think to myself, 'Oh, I'm a little tired', and I would look to my left, and there would be Gummy bears. It was pretty magical".

Meanwhile, Eddie turned to caffeine to stay wide awake on set: "One of the things I find weird about filmmaking is you can be filming wide shots and big things in the morning, and then everyone stops for lunch, and you’re feeling slightly tired afterwards, and you have to go straight into a close-up or an emotional thing.

"That's why, basically, I'm a coffee addict. Katherine gave me a lot of grief on the first film about drinking so much coffee".

"I've never seen one man drink so much coffee in all my days," the actress laughs.