The Constitution Party will hold a press conference on Wednesday where it will likely announce its support for Hamdeen Sabahi's candidacy in Egypt's presidential elections, a source told Ahram Online.
Speaking on the condition of anonymity, the source said Sabahi will be present during Wednesday's press conference.
If the Constitution Party does announce their support for Sabahi, they would be the first political party to do so after Hamdeen's Karma Party. Sabahi is also already backed by the Egyptian Popular Current Movement, which he heads.
Constitution Party head Hala Shukralla previously said in an interview with Ahram Online that "by default, putting the military in the political scene affects the mechanisms for democracy entirely."
Sabahi and former defence minister Abdel-Fattah El-Sisi are Egypt's strong contenders in the upcoming presidential elections.
El-Sisi, who resigned from his position to run for president, announced the ouster of Morsi on live television on 3 July in the presence other political, national and religious figures.
Shukrallah won the liberal Constitution Party's elections in February to succeed Mohamed ElBaradei as the party's president.
ElBaradei resigned as party head when he was appointed vice president following the Morsi's ouster. He then left the interim cabinet to protest the violent dispersal of the pro-Morsi Rabaa Al-Adaweya protest camp which left hundreds dead.
Morsi was ousted after three-day mass protests demanding early presidential elections.
The presidential elections will take place on 26-27 May.