Sir Mo Farah has backed a charity appeal to help the millions of people who face starvation in East Africa.
The Disasters Emergency Committee's new East Africa Crisis Appeal seeks to help the more than 16 million people in the region who are "on the brink of starvation and in urgent need of food, water and medical treatment".
Around 800,000 children aged between six months and five years in Somalia, Kenya, Ethiopia and South Sudan need lifesaving treatment for severe acute malnutrition, the DEC said.
The DEC appeal will be broadcast on Wednesday across all major channels in the UK and comes after ITV News highlighted the plight those in need through the Fighting Famine coverage.
Sir Mo, who spent his early childhood in some of the worst affected areas of Somalia, said he was "completely devastated", urging people to "act now".
The quadruple Olympic champion was speaking as he was named ambassador for Save the Children, one of 13 UK aid agencies brought together by the DEC.
He said: "As a father of four, it hurts to see children without food and water, but this is a reality being faced by parents in East Africa right now.
"The drought is really bad and there are millions of children at risk of starvation.
"I was born in Somalia and it breaks my heart to hear stories of how families are suffering."
Money raised by the DEC appeal will help those in the four affected countries with the government pledging to match public donations pound for pound, up to £5 million.
Earlier this month, the United Nations said the world faces its largest humanitarian crisis since 1945 with over 20 million people in four countries facing starvation and famine.
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."
DEC chief executive Saleh Saeed said: "We are hearing that families are so desperate for food that they are resorting to eating leaves to survive. This is something no family should have to endure.
"Unless we act now the number of deaths will drastically increase."
Members of the public can donate to the DEC East Africa Crisis Appeal by texting the word SUPPORT to 70000, visiting www.dec.org.uk, or calling 0370 60 60 610.