The Prime Minister of Pakistan is the Head of Government of Pakistan who is designated to exercise as the country's Chief Executive. By the Constitution of Pakistan, Pakistan has the parliamentary democratic system of government. The current Prime minister of Pakistan is Yousaf Raza Gillani of Pakistan Peoples Party. He successively completed 4 years of premiership on 25th March, 2012, and thus became the longest serving prime minister in the history of Pakistan.
"I Muhammad Ali Jinnah, do solemnly affirm true faith and allegiance to the constitution of Pakistan as by law established, and that I will be faithful to His Majesty King George VI, his heirs, and successors in the office of the Governor-General of Pakistan".