The Royal Family registered the 'Reina Letizia' trademark almost eight years ago, Spanish newspaper La Expansión reported on Tuesday.

At the same time, the family also registered other names including that of Letizia's husband, Spain's Príncipe Felipe (Prince Felipe).

Other names and titles registered included Prince Felípe's title of Príncipe de Asturias (Prince of Asturias), Princesa de Asturias (Princess of Asturias, or Letizia's current title), Princesa Letizia, and that of the Infanta Leonar de Borbón.

In 2007, the royal family added the trademark Infanta Sofía de Borbón to that list. 

Leonar and Sofía are the children of Prince Felípe and Princess Letizia and the the grandchildren of the current King Juan Carlos and Queen Sofía.

La Expansión also noted that Kate Middleton's name had been registered at the UK Intellectual Property Office several months ago. This was done so that only products to be sold by the charitable Royal Foundation of the Duke and Duchess of Cambridge and Prince Harry could bear her name. 

In Spain, trade names are registered at the Office of Trades and Brands (OEPM). Registering a single name costs €500 ($645) for a period of 20 years but the practice is rare in Spain.

Occasionally, the names of famous people are registered fraudulently, as was the case with Spanish goalkeeper and team captain Iker Casillas.

In December 2012, Casillas attempted to register his name as a trademark so that he could sell clothing and footwear. On doing so, however, he discovered that a Portuguese man had already beaten him to it.

Casillas then had to prove that he greater rights to use of the trademark than the other party involved in the matter, La Expansión reported.