The 64-year-old Socialist Popular Alliance MP Abul-Ezz El-Hariri has declared his intention to run for the Egyptian presidency.
Earlier this week he said he would not stand but announced a reversal of his position during an interview on the Al-Arabiya satellite channel on Tuesday.
El-Hariri represents West Alexandria and is head of the Revolution Continues Alliance (RCA) of liberal, moderate Islamist and socialist parties. The alliance won a limited number of parliamentary seats but its supporters see it as the "revolution's voice" in parliament.
The Presidential Election Commission announced late February that elections would take place on 23/24 May, with results announced on 21 June.
The floor opens for official candidacy submissions on 10 March.