Abhishek appeared on Friday's episode with his friend and director Goldie Behl to promote their forthcoming action fantasy film "Drona" slated to release Oct 2.
"This is the most ambitious and biggest film I have done till now, " Abhishek said in a tête-à-tête with show host Shilpa Shetty.
In an unexpected turn of events, Abhishek then entered the "Bigg Boss" house and the excitement and joy of the house-members knew no bounds.
Before the actor's entry, the participants were assigned a task to dress up a mannequin as "Drona" - a warrior. They were provided with an outfit similar to the one Abhishek wears in the film.
Item girl Payal Rohatgi was quick to decipher the purpose behind the task and said: "'Drona' is the name of an upcoming film and has Abhishek Bachchan and Priyanka Chopra. It must be a tie up."
When Abhishek surprised the inmates with his presence, all of them were overjoyed since they were seeing someone outside of the house after a long time and because it was none else than Bachchan Junior. The star had brought with him a bag full of goodies for the reality show participants.
Item girl Sambhavna Seth, dubbed the controversy queen of "Bigg Boss", and co-participants Rahul Mahajan, Zulfi Syed and Ehsaan Qureshi were constantly following the actor around.
Sambhavna kept insisting that Abhishek eat a bowl of 'kadhi' cooked by her and also expressed her desire to have a candlelight dinner with him. Payal prepared tea for Abhishek and all of them took him on a tour of the specially designed "Bigg Boss" house - including the washrooms.
The reality show requires celebrities to be locked up in a specially designed house for three months under 24-hour camera surveillance, with no access to the outside world. Every week one housemate is evicted and the one who stays till the very end emerges the winner.
The vote-out happens every Friday and this time Abhishek was asked to do the honours. TV actress Shweta Tiwari's estranged husband Raja Chaudhary was Friday asked to leave the show.
Abhishek left the house soon after the vote-out took place.