New Delhi: Bollywood superstar Aamir Khan was on Wednesday appointed the national brand ambassador of UNICEF to promote child nutrition and the actor said he takes his new job as a responsibility and not as a burden.

Aamir is the third Bollywood celebrity after Amitabh Bachchan and Priyanka Chopra to represent United Nations International Children's Emergency Fund in India.

The 46-year-old actor, who will be working towards solving the problem of malnutrition in children under two years, said he is honoured to be a part of the UNICEF family.

"I am humbled to be here on Wednesday...I don't take this as a burden but as a responsibility. It has been a joyful process being a part of this wonderful team (UNICEF). It has been a satisfying and enriching experience for me to work towards the betterment of the children in our country," Aamir told reporters after being appointed the ambassador.

"I was amazed to know the facts when I joined UNCIEF that how much do our children suffer from diseases and how little is done about it. For me the journey began a year and half ago when a group of young MP's came up to me from citizen alliance against malnutrition saying that they wanted me to be a part of the cause for fighting these issues."

Aamir, who has also been the face of Indian tourism, said he plans to reach out to the masses through advertisements.

"I will try and give my best for this cause and look forward to the future where children our happy and healthy," Aamir said.

The actor-producer, know for his films like 'Taare Zameen Par', '3 Idiots', 'Ghajini' and 'Dhobi Ghat', said he will use his movies to make a difference in society.

"I took two years to make Taare Zameen Par and it was a very emotional journey. I have always been very sensitive to social issues and I know that I alone cannot make a difference but it just satisfies me to know that I am doing my part to improve things."

He is known as the 'Mr Perfectionist' in Bollywood, but Aamir says he does not believe in any success mantra.

"There is no sauces mantra! Whatever I do I do it from the heart and give my 100 per cent. I never think about success. What is important for me is the journey towards the goal. If I enjoy the journey then I know I can make it."