On Tuesday, Big B shot for "Kaun Banega Crorepati" (KBC) and finished his shoot for the day, but during the night, he didn't feel too well.
The 71-year-old tweeted: "Yes...went to work! Back for quite a while...and the fever has returned!! DAMN."
He took a day off Wednesday and tweeted: "The time it takes for one to adjust to a day of rest, is akin to time taken for an entire lifetime...or so it feels."
A source from the set of KBC said Bhachchan couldn't come for the shoot Thursday and that he must take rest.
So now, the KBC team is likely to reschedule his shoot to next week, the source added.
At his age, Big B is one of the most active Hindi film veterans and he keeps himself occupied with TV and film projects.