Daniel Radcliffe didn't eat for two days while filming the new survival movie 'Jungle'.

The 28-year-old actor is currently starring in the new movie by Greg McLean about the real-life survival of Yossi Ghinsberg - who had to survive in the Amazon jungle alone after an accident - and Radcliffe admitted he lost a dramatic amount of weight.

Speaking on 'Lorraine' on Thursday (19.10.17), Radcliffe said: ''I had a fillet of white fish and a protein bar a day. I didn't eat for two days, it is not a healthy thing to do. I do not advise anyone doing it but I was doing it for a very short time. It was worth it for the meal I got at the end of filming. I'm not a method actor at all but I felt like I would be making my job harder and not doing justice to this guy's story if I was going home each night to a steak dinner and living really comfortably.

''Nobody really asked me to do it, it was kind of self-inflicted but I think it was needed.''

Radcliffe, who shot to fame as young wizard Harry Potter, admitted his family and girlfriend Erin Darke were worried about his health and admitted losing that weight did ''mess'' with his head.

He said: ''A lot of people were very worried about me. It took me a while to get back to eating properly afterwards. It does mess with your head a bit.

The film follows Yossi who is escorted by a mysterious guide into the Amazon jungle with his friend but their journey turns into a terrifying ordeal as the darkest elements of human nature and the deadliest threats of the wild force them to fight for survival.

Radcliffe explained why he decided to take on this role and said it's a story that needs to be ''widely known''.

He said: ''It was definitely one of those stories that you hear and go 'wow, this should be more widely known'.

''I wanted to be a part of further telling that story and getting it to a wider audience.''