The 41-year-old is a longtime ambassador of the global welfare charity and has spoken out to highlight the latest humanitarian crisis facing Africa, reported Femalefirst.
"Children in west Africa are at risk from starving to death. Drought, rising food prices, and a harvest devastated by insect plague have created a humanitarian crisis on the verge of a disaster.
"Over one million children are at risk from starving to death. But we can stop these children from dying... Children need your help and they need it now," he said.
McGregor has previously worked for Unicef campaigns and given aid to Pakistan and east Africa. The actor also visited India, Nepal and Congo with a mission to immunise children. PTI CORR NDS