In a new video interview released yesterday, the Bollywood star shares his personal mission to eradicate polio.
"Each child must survive and thrive," Bachchan says. "And for that, the world needs more Immunization."
According to a UN statement, Bachchan joins a growing number of international celebrities who have supported the campaign, including Beyonce, Kid President, Jennifer Lopez, Susan Sarandon, LL Cool J, Geena Davis, Trey Songz and Christina Applegate.
The World Humanitarian Day music video for Beyonce's song 'I Was Here', the centre piece of last year's campaign, has been nominated for an MTV Video Music Award for Best Video with a Social Message.
The VMA's are taking place on 25 August.
'The World Needs More__' campaign, produced in collaboration with Leo Burnett New York, allows brands and the public to sponsor a word they believe the world could use more of.
Gucci, Intel, Western Union, Barclays Bank, and Crescent Enterprises have already sponsored words.