The 32-year-old actor later took to Twitter and urged fans to join him in the cause, reported Daily Star.
"(This week) I start living below the line to help Unicef stop children suffering from hunger. Take the challenge too. The World Bank defines poverty as living on less than 1 pound a day," Hiddleston posted.
"The challenge is to buy all the food and drink you need to survive for five days with just 5 pounds (one pound per day)," he added.