The 43-year-old plays a southern fugitive living on a Mississippi island awaiting his true love. In order to make the portrayal accurate, he spent some time alone on a deserted island in Arkansas.
"The only neighbours were a few snakes and two donkeys. It was pretty cool," femalefirst.co.uk quoted McConaughey as saying.
The actor was so determined to embrace the great outdoors that Nochols and the film crew had to drag him away after several days.
Jeff added: "I think he stayed two or three nights, then we had to go get him."
"Mud" also stars Reese Witherspoon.