The Governor of Sokoto state,
Both Tambuwal and Saraki defected from the ruling All Progressives Congress, APC, to the Peoples Democratic Party, PDP in August 2018.
Tambuwal, who was the immediate ex-Speaker of the House of Representatives picked the presidential nomination form of the PDP on August 30, 2018.
The Governor visited the Wadata Plaza headquarters of the opposition party in Abuja with his supporters on Thursday evening to pick his form for the race.
PDP's list of presidential aspirants expands
Tambuwal, the incumbent Governor of Sokoto State, was Deputy Chief Whip of the House of Representatives between 2007 and 2011 after which he became the Speaker of the House of Representatives of Nigeria between 2011 and 2015.
He was a member of the People's Democratic Party (PDP) until he dumped the party for the All Progressives' Congress (APC) in the run-up to the 2015 general elections. He dumped the APC in July 2018 and returned to the PDP and has now joined the opposition party's growing list of aspirants hoping to win its presidential ticket.
He will battle Senate President, Bukola Saraki former vice president, Atiku Abubakar, Gombe State governor, Ibrahim Dankwambo, and former governors, Sule Lamido, Attahiru Bafarawa, Jonah Jang, as well as Rabiu Kwankwaso, who's also a serving senator.