Pranab Mukherjee, who has been selected as the UPA's Presidential nominee, will resign on Sunday as the union finance minister.
"I will resign on June 24", Mukherjee told reporters Kolkata before leaving for his ancestral house in Birbhum district.
Earlier sources had said that Mukherjee is expected to file his nomination papers for the Presidential election on June 28.
Four sets of nomination papers, each having 50 proposers and seconders, are being readied for the nomination, parliamentary affairs minister Pawan Kumar Bansal had said recently.
Besides Prime Minister Manmohan Singh and UPA chairperson Sonia Gandhi, several Union ministers as also leaders of constituent parties of UPA are expected to be the proposers and seconders of Mukherjee's candidature for the July 19 election.
As part of preparations, MPs of constituent parties of UPA and supporting parties have been asked by Mukherjee's election campaign managers to sign the nomination papers kept in Parliament house.