CAFOD, Christian Aid, Tearfund and World Vision are among 13 UK charities coming together under the umbrella of the Disaster Emergency Committee (DEC) to respond to the severe food shortages happening in Somalia, Kenya, Ethiopia and South Sudan.
The DEC says between all four countries, 800,000 children of five years and under are suffering acute malnutrition and need lifesaving treatment.
Fergus Conmen, head of Africa at the Catholic humanitarian charity CAFOD, told Premier's News Hour: "It's really important to recognise the dignity of each of those human beings who are suffering.
"These are not facts and figures, these are human beings who are really in a desperate, desperate situation. When we see such suffering, we have to do all we can to help.
Explaining how Christians can be interceding in the crisis, he went on to say: "We have to be praying, first of all, that food is able to be delivered.
"We have to pray that the rains come in April and May. We have to pray that there's a good harvest and we have to pray for where there's conflict, that there's a stop to the conflict."
The United Nations declared a famine in South Sudan in February.
North-east Nigeria is also being affected by a chronic lack of food, exacerbated by fighting between Islamist Boko Haram terrorists and the country's army.
Oenone Chadburn, head of humanitarian support at Tearfund, told Premier families without enough food can end up in desperate situations, adding: "Sometimes they sell vital pieces of equipment - farming equipment - or maybe they'll sell their animals.
"These are a vital part of the way that hey earn their money and so when they do these things they have some respite for a period of time but then they don't know where next to go."
Oenone Chadburn went on to say: "It's hunger on a massive scale and if we don't deliver life-assisting food and support right now, then there are significant numbers of people who could be at risk of starvation."
International Development Secretary Priti Patel said: "Britain has acted without hesitation - UK aid funded food, water and emergency healthcare is being delivered across East Africa right now, but more support is urgently needed to prevent a catastrophe.
"The international community must now follow Global Britain's lead to save lives and stop the famine before it becomes a stain on our collective conscience. The world cannot afford to wait."
Listen to Premier's Maria Rodrigues speaking with Tearfund's Oenone Chadburn:
Listen to Premier's Alex Williams speaking with CAFOD's Fergus Conmee: