Megastar Amitabh Bachchan says he practices what he preaches and took his granddaughter Aaradhya for polio drops.

"Two drops of the polio vaccine to Aaradhya... overseen by government officials. Just so it is put on record. To practice what I preach," Amitabh tweeted Thursday night.

The 70-year-old veteran is an active spokesperson for the government's polio eradication campaign.

Aaradhya, daughter of Abhishek Bachchan and Aishwarya Rai, got her first drops in April this year. The toddler will turn one Nov 16.

Amitabh says the procedure "went well", and suggests it is not at all painful for children.

"The little one does not get an injection... it is just literally two drops of the polio vaccine into their mouths. Went off well," he added.