Jayant Chaudhary, president of the Rashtriya Lok Dal will be the third candidate supported by the Samajwadi Party for the Rajya Sabha biennial elections.
The party has already announced its support for Kapil Sibal, who is contesting as an independent candidate. Another SP nominee is Javed Ali.
By announcing support to Jayant Chaudhary, the Samajwadi Party has made the first move to cement the SP-RLD alliance for the Lok Sabha elections.
Jayant is expected to file his nomination papers on Friday.
The RLD has eight MLAs in the Uttar Pradesh Assembly and a candidate needs 37 votes to win the seat.
Meanwhile, Samajwadi Party sources said that the party was likely to field Dimple Yadav in the upcoming by-election on the Azamgarh Lok Sabha seat.
The seat had fallen vacant after Akhilesh Yadav resigned from the Lok Sabha in March and opted to remain active in state politics.