"Hema ji joins us tomorrow for the shooting of 'Aarakshan'...a cameo but all looking forward to her arrival..'Baghbaan' remembered," Amitabh wrote on micro-blogging site twitter said.
'Aarakshan' is based on caste based reservations in government jobs and educational institutions.
Other than Bachchan, it stars Saif Ali Khan and Deepika Padukone in pivotal roles, besides, Tanvi Azmi, Prateik Babbar and Manoj Bajpayee. It is expected to release in August this year.
The acclaimed actress-dancer, who is also a BJP leader, has just filed nomination from Karnataka for Rajya Sabha. If elected, this will be her second stint in the Upper House of the Parliament.