Actor Nicholas Hoult struggled to stomach the fake brains he munched for new zombie movie Warm Bodies because it was made of soggy sponge cake.

The British star plays the role of R, who wanders around a post-apocalyptic America feeding off humans, and during one scene he kills Perry Kelvin, played by Dave Franco, and eats his brains.

Prop experts threw together several ingredients to make the fake brains, and Hoult admits the concoction wasn't very appetizing.

He tells JustJared.com, "The human brain was like a peach, soft, wet, spongy sort of thing, and then bits of grapefruit and stuff. It was really, really rough. And there was one take where I was lashing at Dave Franco's head, they used a dummy obviously, they couldn't use his real head unfortunately.

"But then I remember one take where the dummy's hair was kind of getting ripped out by my hand, and then I had to pretend to eat the brains obviously. I remember taking out the brains and seeing all the dummy's hair in the brains, and I was like, 'Ugh!' I had to get the take so I was like, 'Just do it, do it!' So I munched on them and ate a lot of fake hair as well. It's great for your digestive system."