Medal for Harry as Chelsy looks on

Harry's girlfriend sat with his brother Prince William and father the Prince of Wales in seating reserved for VIPs during the ceremony at Combermere Barracks in Windsor.

The young royal was one of 170 members of the Household Cavalry Regiment being decorated for their service in Helmand Province in southern Afghanistan.

With well-wishers lining the streets, the royal soldier and his comrades paraded in full desert camouflage to a thanksgiving service at Windsor's garrison church Holy Trinity. Meanwhile Harry's guests Chelsy and William, who wore a plain suit with a navy and burgundy Household Division tie, were whisked to the church in a chauffeur-driven Jaguar.

The 23-year-old prince, known as Lieutenant Wales, secretly served as Forward Air Controller from December last year until February of this year at Garmsir and Musa Qaleh. But the planned four-month tour of duty was cut short after 10 weeks when a media blackout broke down, forcing him to return home.

Having served more than the minimum one month in a theatre of war he qualified for a campaign medal - the first Royal to see action since the Duke of York in the Falklands 26 years ago.

The Princess Royal, who is colonel of the Regiment's Blues and Royals, placed the Afghanistan Medal on her nephew's chest in the unglamorous setting of the tank maintenance depot at Combermere Barracks.

Harry blushed and struggled to contain his laughter as he shared a private joke with his aunt while his father, brother and girlfriend watched from the front row.

Chelsy, dressed in a white fitted jacket, black top and a dark brown moleskin skirt with calf-length boots smiled and chatted with William as the medals were presented. Although she has been a regular at polo events and attended last year's Concert for Diana, it was the first time she has been pictured at such a formal event alongside Charles and other members of the family.

The Zimbabwean-born university student later joined hundreds of Army wives and girlfriends for the thanksgiving service. Afterwards she left with Harry and William for a private reception back at the barracks.