The actor has joined other celebrities to invite young students to use their superpower to help protect our planet and achieve the global goals' mission to end poverty and inequality.
The World's Largest Lesson aims to teach children in over 100 countries about the new Sustainable Development Goals that will be adopted by the UN General Assembly later this month.
The "Krrish" star has joined other international public figures such as PLAN global ambassador Freida Pinto, Dani Alves, Kolo Toure, Neymar Jr., and Nobel Peace Prize laureate Malala Yousafzai.
"The World's Largest Lesson will do more than teach children about the global goals. It will engage them in the effort to achieve those goals - educating them about the challenges that are shaping their futures and encouraging them to drive change in their own communities," Unicef executive director Anthony Lake said in a statement.
"Young people can help achieve the global goals by holding their leaders accountable for the promises they are making - and by holding themselves accountable for building a better future for everyone," Lake added.
The campaign is also supported by Indian NGOs the Akshaya Patra Foundation and Magic Bus.
Especially created lesson plans include an animated film by author and education expert Ken Robinson that introduces the Global Goals, and a downloadable comic book by Josh Elder and Karl Kesel.
Along with Hrithik, prominent public figures like Malala Yousafzai have recorded their own introduction to the World's Largest Lesson as well. The animated film invites students to consider the creative superpower they have and use it to help change the world for the better.
Additional lesson plans and information are available for teachers to select based on the themes most relevant for their pupils.
"The World's Largest Lesson is a fantastic opportunity to tell all children, everywhere what the Global Goals are and how they can play their part to make sure they are achieved," said Richard Curtis, founder of the Global Goals campaign.
Hrithik is passionate about Goal 3 - Good Health & Well-being, and has always believed that it is with good access to healthcare and quality nutrition, that an individual can reach his or her full potential.
The father of two boys said: "As a father, I believe that all children should have access to good education and through this education they learn how to take care of their health. In order to achieve the best, they need to be fit and healthy. It enables children to push their extreme. These are fundamental rights that every child deserves hence I champion Goal 3 Good Health."
The World's Largest Lesson provides an opportunity to foster global citizenship in schools across the world. It supports student learning across a range of subject areas such as science, geography, citizenship and technology and helps teachers explore important global issues such as human rights, poverty and climate change.