Spain’s King Juan Carlos is due to sign a law allowing his own abdication later on Wednesday in a ceremony at the royal palace in Madrid.
It will be his last act as head of state after a 39 year reign.
Parliament voted yesterday to approve the abdication law, paving the way for his son Prince Felipe to take the throne.
The King, who led Spain’s transition from dictatorship to democracy has recently faced damaging scandals and a fall in popularity. He has also had health problems in the last few years.
On Thursday the prince will be crowned King Felipe VI and his wife, Letizia, a former TV presenter, will become queen.
Security is tight in the capital with more than 7,000 police and security deployed.