Meanwhile, Punjab Chief Minister Prakash Singh Badal has already declared that he will join Mr Modi in Ahmedabad tomorrow.
Earlier, Gujarat Chief Minister declared his fast on Tuesday, Sept 8 in an open letter and the announcement was also supported by his party.
"Glad to see the overwhelming solidarity for Sadbhavana Mission. People are also joining in large numbers through missed call on 022-61550770 (toll-free)," Modi tweeted on Friday (Today).
Sources said that Modi will not be the only person fasting that Gujarat will witness on Saturday, Sept 17. Shankersinh Vaghela, who quieted BJP 15 years ago and joined Congress has said his fast will begin before Mr Modi's and end two hours later. Mr Vaghela says his fast hopes to change the notion that Mr Modi has been given a clean chit by the Supreme Court.