YSR Congress Party chief YS Jaganmohan Reddy on Friday filed nomination for the May 8 by-election to the Kadapa Lok Sabha seat.
Jagan, as he is popularly known, filed the papers before the returning officer at the district collectorate in Kadapa.
Accompanied by a large number of supporters, the young leader reached the district collector's office after taking the blessings of his mother Vijayalaxmi.
YSR Congress Party exuded confidence that Jagan will retain the seat. "There is no doubt that Jaganmohan Reddy will win the by-election with a bumper majority," said his supporter and actress Roja.
Earlier, Jagan visited his father YS Rajasekhara Reddy's grave at Idupulapaya family estate in Kadapa district to seek his blessings.
The ruling Congress has fielded state Health Minister DL Ravindra Reddy while the main opposition Telugu Desam Party (TDP) has named Rajya Sabha member MV Mysoora Reddy as its candidate.
Jagan's mother will file her nomination for Pulivendula assembly seat Saturday. She is pitted against her brother-in-law and state Agriculture Minister YS Vivekananda Reddy.
The by-elections are necessitated by the resignations of Jagan and his mother as MP and legislator respectively in November last year.
They also quit the Congress, accusing the party leadership of trying to divide the family by wooing YSR's younger brother Vivekananda Reddy with a ministerial berth.
Jagan launched the new party last month, with a promise to continue the pro-people policies of his late father.
YSR died in a helicopter crash in September 2009, five months after he led the Congress to second successive electoral victory in the state.
Jagan, who made his electoral debut by winning the Kadapa Lok Sabha seat in 2009, was ignored by the leadership when his loyalists demanded that he be made the chief minister, succeeding his late father.
In the December 2009 by-elections to Pulivendula caused by YSR's death, his widow was elected unopposed.