Taking to Twitter, Bachchan shares a collage featuring him and Kapoor and a note, which reads "happy birthday".
"Happy birthday Shashi ji... And to some of the most exciting and adventurous times spent together .. on set .. off set..," he writes.
Bachchan, 74, and Kapoor have worked together in many films like Deewaar, Suhaag, Kabhie Kabhie, Trishul, Silsila and Namak Halaal.
In 2009, Bachchan also mentioned Kapoor in his blog, writing, "In Mumbai, Shashiji had always been a great support.
"I would visit him on set when I was looking for a job, he already being an established star by then, and he would introduce me to all his directors."