The biggest secret that the royal family has hidden from Spanish society is that, after the Infanta Elena (1963), the Infanta Cristina (1965) and King Felipe (1968) were born, Juan Carlos I had a fourth daughter, the fruit of of an extramarital affair with an aristocrat slightly older than him. This fourth heiress came into the world in the late seventies, early eighties. Her name is Alejandra, she is married, has a son and has never claimed any type of succession right. She grew up ignorant of who her father really was and, when she finally found out, she chose to continue to act as if the news had never reached her ears.
The data is precise enough to understand the size of this gap in the official history of an essentially genetic institution like the monarchy. But, at the same time, they are vague enough to protect the identity of the principal affected, who prefers to remain anonymous.
All the tenants of the Palacio de la Zarzuela know of Alejandra's existence, although she was not always like that. When Felipe VI was young, Juan Carlos I feared that he would meet his stepsister and the two would fall in love without knowing that they were family. When Alejandra was finally informed that her father was the King of Spain, a discreet rapprochement ensued. The then head of state tried to compensate for the lack of official recognition with affection and other signs of generosity, although he never treated her like his other three children.
Over the years, the confidence went beyond the walls of the Palace and began to be shared by the King with his circle of friends. He said that she was a good girl, very intelligent and prepared. He seemed proud of her, although he didn't give many details about her either.
Alejandra's existence has been confirmed by three people. The first is a former lover of the King emeritus to whom he confessed the paternity of the young woman. Subsequently, that ex-partner received the same information from other people in the monarch's environment. The second is a businessman with whom Juan Carlos I has shared a friendship for six decades, who knows the story and who has seen the King and Alejandra interacting as naturally as any father and daughter would. And the third source is Alejandra's old boyfriend, whom she is she also recognized her link with the royal family. Juan Carlos I and Alejandra's mother met when they were both young. They shared friends and a passion for hunting.