Jagan, as the MP from Kadapa is popularly known, will begin the fast Sunday morning, party leader K. Ramakrishna said.
Jagan's decision was announced soon after his wife Bharathi and several party leaders called on him.
He has spent more than a year in jail in a disproportionate assets case.
Earlier, his mother and the party's honorary president Y.S. Vijayamma called off her fast at his request.
Jagan spoke to her over the phone and urged her to break her fast in view of her deteriorating health.
Vijayamma, the widow of former chief minister Y.S. Rajasekhara Reddy, was continuing her fast on the sixth day Saturday, despite being forcibly shifted to a hospital in Guntur by the police after her condition started deteriorating.
She was later discharged from the hospital and left for Hyderabad.
YSR Congress workers resisted the police attempt to move Vijayamma to hospital, leading to tension. Police used mild force to disperse the protestors.
Vijayamma is demanding that the centre not bifurcate the state if it cannot render justice to all the regions.
Vijayamma and 16 other state legislators of the party and both its MPs have submitted their resignation to protest the manner in which the United Progressive Alliance at the centre decided to divide the state.
Meanwhile, police also forcibly shifted Telugu Desam Party (TDP) legislators N. Rajkumari, Y. Srinivasa Rao and former minister S. Aruna to hospital early Saturday. They were also on fast since Monday.
Both YSR Congress and TDP have called for a shutdown in Guntur against the police action. Shops, business establishments and educational institutions remained closed in the town.
Protests continued in Seemandhra (Rayalaseema and Andhra) for the 25th day against the bifurcation of the state.
More than six lakh government employees, including two lakh teachers in 13 districts of Seemandhra, were continuing their strike, demanding that the centre reverse its decision.
Road transport remained paralysed for the 12th day with over 12,000 buses of state-owned Andhra Pradesh State Road Transport Corporation (APSRTC) remaining off the roads.
--IANS (Posted on 24-08-2013)