The funnyman, who recently became a first-time father with his model wife Lara Stone, joined the kids at Cameron's official London residence, 10 Downing Street, to show their support for the Enough Food for Everyone If campaign.
Cameron was presented with a specially crafted plate by each of the children in attendance, representing more than 30,000 plates decorated by youngsters across the U.K. ahead of the Nutrition for Growth Summit in London on Saturday (08Jun13).
Walliams urged the Prime Minister to build on existing commitments to nutrition programs at the upcoming summit and said, "Now is the time for our Government to go further and show the rest of the world's leaders that we're serious about ending global hunger and poor nutrition.
"As part of my work for (U.K.charity) Comic Relief I've seen first-hand the devastating impact that hunger and malnutrition have on children, denying them the opportunity to grow, play and learn. Bold action at Saturday's Nutrition for Growth event would truly change children's lives."
If Campaign supporters are asking attendees at Saturday's Nutrition for Growth Summit to commit to mobilising an additional $1 billion annually to help end global malnutrition.