Kejriwal, who was Anna's lieutenant in the anti-corruption movement three years ago, came to the Maharashtra Sadan and met the Gandhian for the first time after the two had gone apart two years ago when AAP was formed.
Deputy Chief Minister Manish Sisodia made the announcement about Kejriwal's participation in the protest in the afternoon which may be of symbolic nature.
While Sisodia parried a question whether Kejriwal would share the dais, Hazare had earlier said that AAP leaders were welcome to sit with the protesters.