Keira Knightley emotional during Chad charity trip

Keira Knightley was overcome with emotion on a charity trip to West Africa after witnessing the plight of malnourished children living in poverty.

The Atonement star made the trip to Chad to support UNICEF, and she was stunned when she discovered the conditions youngsters are living in.

Footage of Knightley's trip aired in a U.K. TV special on Wednesday night (23May12), in aid of the upcoming Soccer Aid fundraiser, and showed the 27 year old touring a nutrition center set up to help those in need.

She said, "This area is currently in the grips (sic) of one of the worst food crises in years. In an emergency like this, children are often the first to pay the price. UNICEF and their partners are here trying to tackle this catastrophic situation.

"They've set up this nutrition center to provide direct and immediate care to children who are victims of the crisis."

Knightley met young children at the unit, and gasped in horror as she declared of one tot, "She's swollen so her whole body is swollen up, all around her eyes is full of liquid. As the body swells the skin shrinks so it splits."

She also urged viewers to hand over $8 donations, adding, "With your help UNICEF can save children's lives... please text the word 'Donate' to 70442."

The Soccer Aid match takes place in Manchester, England on Sunday (27May12) and will feature stars including Will Ferrell, Michael Sheen and Robbie Williams competing for charity.