"Aamir Khan on set today (Friday)...drops by to say hello! and waves to the 'KBC' guests! We talk of 'Dhoom 3'," Bachchan posted on Twitter late Friday night.
Releasing Dec 20, the action-adventure thriller also stars Abhishek Bachchan, Katrina Kaif and Uday Chopra in lead roles and has been produced by Aditya Chopra under Yash Raj Films banner.
Actress Kajol will visit the quiz show's sets as a part of the Children's Day celebrations. All the money won by the actress will go to a children's charity.
"Tomorrow it's the lovely Kajol on set playing for a cause," Bachchan posted on his blog.
The three-day Children's Day celebrations will begin Nov 8. They will also see finalists of "Indian Idol Junior" on the hot seat as well as five-year-old Kautilya Pandit, who was awarded Rs.10 lakh by the Haryana government for his exceptional intelligence quotient (IQ) and memory earlier this month.