He has maintained contact with the community since then.
Prince William completed more than seven years of military service, after his officer training at Sandhurst. His finished his military career as a search and rescue helicopter pilot at RAF Valley in Anglesey, in 2013.
“It is with a deep sense of honour and respect that I accept your invitation to become patron of the Special Air Service Regimental Association,” he said.
“The SAS has long stood as a symbol of courage, resilience and unwavering dedication to duty and the service of this country.
“The association continues that camaraderie forged on the battlefield and provides essential support to its members and families.”
He also pledged to help ensure “the sacrifices and achievements of SAS members past and present are recognised”.
As a senior member of the royal family, the prince is affiliated to a number of military regiments.