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.
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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.