Vice President Mahmoud Mekki has resigned, announced the presidency in a statement released on Saturday in the early evening hours.
No reasons were given to explain Mekki's resignation.
The announcement comes on the day of the final round of constitutional referendum, The draft constitution does not mention the post of vice president and it is therefore inferred that the post has been removed.
Mekki is the country's first civilian to serve as vice president since Egypt's 1952 revolution.
A reformist judge, Mekki is most well-known for fighting for judicial reforms against former president Hosni Mubarak's regime as part of the Egyptian pro-democracy movement which reached its peak between 2005 - 2006. Mekki, alongside his colleagues, also opposed the rigging of the 2005 parliamentary elections, which were widely held to be fraudulent.
Mekki, however, started his career in the police force, graduating from the Police Academy and serving as a Central Security Forces officer. Later on, he earned a bachelor's degree in law and eventually headed Egypt's Court of Cassation.
His brother, Judge Ahmed Mekki, also was also appointed to a post in President Mohamed Morsi's government, as minister of justice on 2 August.