Diego is a Spanish male name derived from the Hebrew Yaʻăqōbh (Jacob), via the name of Saint James the Greater (Sant Yago), re-analysed as Santiago and San Diego. The assimilation of the final t of Sant into the name is attested in other saints' names, including Spanish and Portuguese Telmo 'Elmo' (< Sant Elmo) and Slovenian Tilen 'Giles' (< Šent Ilen).

Diego is a very popular name in the Spanish-speaking world. In Brazil/Portugal, France and Italy it is a very widespread name as well (as are other Spanish names such as Fernando). For example: due to the Spanish influence from the days of the kingdom of Naples, on the death of king Alfonso I of Naples (also known as Alfonso V of Aragon) in 1458, a famous elegy was composed by one Diego del Castillo.

The patronymic for Diego is Díaz in Castillian (used for example by Rodrigo Díaz de Vivar, better known as El Cid) and Dias in Portuguese. Like many patronymics, these have become common surnames in Spanish- and Portuguese-speaking regions. The form Diéguez is much less common; Diegues can be found in Portuguese-speaking countries. de Diego and Diego can also be found as surnames.

Julio Iglesias (born Julio José Iglesias de la Cueva; September 23, 1943) is a Spanish singer and songwriter whose romantic image, magnetic stage presence, and expressive music made him one of the best-selling artists of all time. By the early 21st century he had sold hundreds of millions of albums in more than a dozen languages. He has sold over 300 million records worldwide in 14 languages and released 77 albums. According to Sony Music Entertainment, he is one of the top 15 best-selling music artists in history. While Iglesias rose to international prominence in the 1970s and 1980s as a performer of romantic ballads, his success has continued on as he entered new musical endeavors. He is the father of singer Enrique Iglesias.

Iglesias was born in Madrid, the eldest son of Dr. Julio Iglesias Puga and María del Rosario de la Cueva y Perignat. Iglesias' father's family was from Galicia, and Iglesias' mother an Andalusian.

In the 1960s, he studied law in Madrid and was a goalkeeper for one of Real Madrid's football teams. On September 22, 1963, he was involved in a car crash, resulting in an injury to his spinal cord. He said, "I had a car accident; [a] very, very strange car accident...I lost control of the car and rolled it, resulting in what they call 'paraparexia,' which is not paraplegia. It's a compression in the [spinal] cord, in the sense of the neck...my spinal cord; and I was very, very ill for three years."  His doctors thought he would never walk again; indeed, his legs were left permanently weakened, and they continued to require therapy as of late October 2010. However, slowly, he began recovering his health. To develop and increase the dexterity of his hands, he began playing guitar. When he recovered from his accident, he resumed academic studies and traveled to the United Kingdom to study the English language, first in Ramsgate, then at Bell Educational Trust's Language School in Cambridge.