Crown Prince Felipe and his wife Princess Letizia will become King and Queen of Spain.
The couple will ascend to the throne following the announcement earlier today that King Juan Carlos is to abdicate.
The announcement was made by the Spanish prime minister Mariano Rajoy who said an amendment will be made to the constitution to allow the abdication take place.
Juan Carlos (76) has battled ill health for some time and his son has stepped into his role for official functions.
The King and Queen Sofia have three children together – Felipe, and older daughters Elena and Cristina.
However, the Spanish royal family has been hit by a number of scandals in recent years.
Cristina has been excluded from official acts since December 2011, when her her husband, Inaki Urdangarin was named as an official suspect in a wide-reaching corruption scandal.
She appeared before a judge in Majorca in February over money laundering and tax evasion allegations linking her to the business affairs of her husband. During the court appearance, which lasted several hours, she was accused of being ‘evasive’ during questioning.
Spain is in the grip of a deep recession – with many criticising the spending of the Bourbon household.
Earlier this year, spending by the royal family was cut to €7.78m – down from €9.4m five years ago.
King Juan Carlos received a salary of €140,000, plus a further €150,000 to cover “cost of representation”.
His son received an amount equalling half his father’s salary and expenses.
In 2013, to further quell public anger in a country where unemployment rose to 27pc, Juan Carlos renounced use of his €21m yacht.
Juan Carlos, 76, oversaw his country's transition from dictatorship to democracy but has had repeated health problems in recent years.
His popularity also dipped following royal scandals, including an elephant-shooting trip he took in the middle of Spain's financial crisis that tarnished his image.
The king came to power in 1975, two days after the death of long-time dictator Francisco Franco.
He is the second European monarch to abdicate in just over a year. In April last year, Queen Beatrix of the Netherlands handed the throne to her son Prince Willem-Alexander after 33 years.
Mr Rajoy broke the news in an announcement broadcast nationwide.
He did not say when Juan Carlos would abdicate because the government must now craft a law creating a legal mechanism for the abdication and for 46-year-old Felipe's assumption of power.
The king endeared himself to many Spaniards by putting down an attempted military coup in 1981 when he was a young and largely untested head of state.
As Spain's new democracy matured over the years, the king played a largely figurehead role, travelling the globe as an ambassador for the country, and was a stabilising force in a country with restive, independence-minded regions such as the Basque region and Catalonia.
But his image was tarnished by the elephant shoot and also by the investigation of his son-in law, who is suspected of embezzling large amounts in public contracts.