Prince Moqren, named last year as second in line to the Saudi throne, was a trusted confidant of the late King Abdullah with a reputation as a liberal.
Born on September 15, 1945 in Riyadh, Moqren is the youngest of the 45 sons of Abdulaziz bin Saud, the founder of Saudi Arabia.
He graduated from Britain's Royal Air Force College and served in the Saudi air force until taking on political roles from 1980.
He was governor of the northern province of Hail, and then of Medina in the west.
In 2005, Moqren was appointed head of Saudi intelligence, a post that helped the prince build a network of international contacts.
In 2012, King Abdullah named him as counsellor and special envoy, and the following year appointed him second deputy prime minister.
Diplomats say Moqren was very close to Abdullah and was frequently entrusted with sensitive assignments.
He has been involved in key foreign policy issues, including in Afghanistan, Pakistan, Syria and Yemen, and is known for his open hostility to Iran, Saudi Arabia's Shiite-dominated arch rival across the Gulf.
Signup to our newsletter and follow us on Facebook and Twitter!
In an unprecedented move, Abdullah named Moqren as deputy crown prince in March 2014, making him second in line to the throne behind then-Crown Prince Salman.
Analysts say that if Moqren becomes king he is likely to press ahead with the limited economic and social reforms launched by Abdullah in the deeply conservative kingdom.
"Moqren may mark the start of a more accelerated reform programme at home," said Frederic Wehrey, Gulf expert at the Carnegie Endowment for International Peace.
"There is already a great deal of pressure from technocrats and the youthful citizenry for the kingdom to modernise domestically if it is going to compete on the global stage," he said.
Moqren's naming as deputy crown prince was opposed by some members of the royal family, with a quarter of the members of the Council of Allegiance that decides on succession issues reportedly voting against him.
Moqren's mother was Yemeni and he would set a precedent if he accedes to the throne by becoming the first king born to a non-Saudi mother.
Twice married and the father of 15 children, Moqren presides over several associations and social organisations, like many other royals.
Moqren is known for his modesty, and interest in agriculture and astronomy. He is also a staunch supporter of developing e-government services in the ultra-conservative kingdom.