Taking to Instagram, Abhishek wrote, "My hero, my idol, my friend, my father! Happy birthday Dad. Love you."
Alongside the note, Abhishek, who is also known as Junior B, posted a video featuring different images of Senior B (Amitabh Bachchan) from different phases of his life.
"A great actor... the perfect great model," the text from the video read.
For the unversed, Abhishek along with wife Aishwarya Rai Bachchan and daughter Aaradhya returned to Mumbai from Paris in the wee hours of Monday, right in time for Amitabh's birthday.
The trio went to Paris earlier this month to attend the Paris Fashion Week, where Aishwarya was one of the showstoppers.