On 1st January 1984, Hassanal Bolkiah, the 29th Sultan of Brunei named himself prime minster of Brunei.
Brunei is a former British protectorate that also gained independence that year. Hassanal, the country's leader and reportedly the richest person in the world on at least some occasions, also granted himself a bunch of other important positions in the government. He is also Yang Di-Pertuan, the title of the Head of State.
Taking so many different positions would probably be a lot more tiring if he wasn't extremely rich and Brunei didn't have a population of only a bit over 400,000 people.
Image: Kremlin.ru [CC BY 3.0 (creativecommons.org/licenses/by/3.0)], via Wikimedia Commons