Former prime minister Manmohan Singh on Tuesday filed nomination papers for the bypoll to Rajya Sabha from Rajasthan.
Singh filed the nomination papers in the chamber of the returning officer in the Rajasthan assembly, sources said.
He was accompanied by Rajasthan chief minister Ashok Gehlot, deputy chief minister Sachin Pilot, All India Congress Committee general secretary in-charge of Rajasthan Avinash Pande, Rajasthan parliamentary affairs minister Shanti Dhariwal, chief whip Mahesh Joshi, health minister Raghu Sharma and others.
The seat got vacant after the death of Bharatiya Janata Party's Rajya Sabha MP Madan Lal Saini in June.
Rajasthan has 10 Rajya Sabha seats.
The Congress has the majority in the state assembly and Singh, 86, is likely to win the bypoll.
The Rajasthan assembly has 200 seats, two of which are vacant.
The Congress has 100 MLAs and its alliance partner Rashtriya Lok Dal has one seat.
The Bharatiya Janata Party has 72 while the Bahujan Samaj Party 6, the Bharatiya Tribal Party, the Communist Party of India-Marxist and the Rashtriya Loktantrik Party have two seats each.
Thirteen MLAs are independents and two seats are vacant.
The ruling Congress in the state also enjoys the support of 12 out of the 13 independents and the BSP legislators.
Singh, a veteran Congress leader, was a member of the Upper House of Parliament from Assam for almost three decades.
He was a Rajya Sabha member for five consecutive terms from 1991 to 2019 and the country's prime minister for two consecutive terms from 2004 to 2014.
Singh's tenure in the Rajya Sabha ended on June 14 this year and he could not be renominated as the Congress did not have the strength to send him to the Upper House from Assam and there was no other vacancy left.
As per the schedule released by the Election Commission, the last date for the filing of nomination papers is August 14.
Scrutiny of papers will be done on August 16.
The last date for the withdrawal of nominations is August 19.
The polling will be held on August 26 while the counting of votes will take place on the same day at 5 pm.