India, May 9 -- Even at 82, superstar Amitabh Bachchan is among the most active Indian actors on Twitter. He uses it to send wishes to his 'extended family' on all festivals, when not praising the latest movies of his son, Abhishek Bachchan. However, lately, his Twitter activity is quite different from usual and fans have noticed it too.

Over the last couple of weeks, Amitabh Bachchan has launched about 20 blank tweets. They simply include different number in chronological order, without any context. His last legible tweet was on April 22: "T 5355 - The silent X chromosome .. deciding the brain .."

Fans have been sharing screenshots of his account, asking others what is happening. "The mystery of the India's speechless (tweetless?) supe...