Will Poulter

The star played a supporting role in Ari Aster's 2019 movie 'Midsommar' - which starred Florence Pugh and Jack Reynor as a US couple who get embroiled in a violent cult on a visit to Sweden - and explained how the film's disturbing content left him unable to sleep at night.

He said: "I had the worst night's sleep of my life the night after. Terrible, terrible, full-on nightmares.

"[The picture] is utterly disturbing. And it's that kind of disturbing feeling that I think lingers longer than a fright. A fright has a very limited lifespan.

"This idea that humans are capable of what you see in 'Midsommar' is kind of what's most disturbing about it.

"Despite reading the script and despite being in it and shooting it, and presumably knowing what to expect, I was still caught massively off guard."