The 70-year-old actor has been the celebrity host of the popular show for five seasons out of six, with Shah Rukh Khan anchoring the third season.
"The season endeth here of KBC! A sadness prevails and there is a feeling of great remorse... A feeling that cannot be described in words," Bachchan posted on Facebook.
"It is the audience that comes so religiously and stays so calm and disciplined... Thank you all... I hope I can be back with you soon... Love to all," he added.
Big B also posted some photos from the sets of the last episode, which bore the theme of Republic Day since it will be aired on January 26.
The sixth season went on air September 7 and Mumbai-based home tutor Sunmeet Kaur Sawhney won the bumper prize of Rs 5 crore, becoming the first woman to win the jackpot on the show.
