"While Bhutan has made amazing progress in areas of health and nutrition, there's still work to be done and every child is yet to be reached," Aamir said in a statement. 

Stunting, caused by chronic malnutrition, is endemic in South Asia with an estimated 38 per cent - 64 million - of children under five years of age affected by stunted growth, inhibiting children's cognitive and physical development and damaging growth in the region. In Bhutan, despite recent progress, one in five children remains stunted, according to Unicef.

The Royal Government of Bhutan, Unicef and partners are working together to improve under-nutrition and micro-nutrient deficiency among children by working with families to improve sanitation practices in households and communities, and improve nutrition of young children and women before and during pregnancy.

Aamir, during his visit to Bhutan on Monday and Tuesday, met Namgay Zam, 26, in the Drukgyel Basic Health Unit in Paro, who had given birth to her baby just 20 days ago. He also interacted with other women and their children at the health unit. 

"It is incredible to meet young mothers in Bhutan and to understand how they have made simple, effective changes to their lives to help keep their children healthy," said the "PK" star.

Rudolf Schwenk, Unicef Bhutan Representative, also said: "We are delighted that Aamir Khan is here in Bhutan to help us shine a light on the impact of under-nutrition and to show how by working together we can reduce stunting in children across the country."