Trooper James Munday was nearing the end of his tour of duty
The latest soldier killed in action in Afghanistan was a colleague of both Princes William and Harry, Clarence House has said.
Trooper James Munday, from Birmingham, died in a blast during a routine patrol in Helmand province on Wednesday.
The princes, who served with the 21-year-old in the Household Cavalry, were "deeply saddened" by his death and called him an "exceptional soldier".
Two other soldiers were also injured in the blast.
Prince William served alongside Trooper Munday in D Squadron of The Household Cavalry, and he was also in the same regiment as Prince Harry.
A Clarence House spokesman said: "Prince William and Prince Harry are deeply saddened to hear the tragic news.
"Together with the rest of their regiment, the two Princes' heartfelt thoughts and prayers are with his family and friends at this most distressing of times.
"Trooper Munday was in D Squadron with Prince William, and he remembers him as an exceptional soldier."
He was killed in "especially tragic" circumstances, shortly before the end of his tour of duty, fellow officers said as they paid tribute to him.
Lt Col Harry Fullerton, his commanding officer, said: "Trooper James Munday was, without a shadow of a doubt, one of the best of his generation.
"He was a rising star in his peer group and a truly brilliant Life Guard and household cavalryman."
The keen sportsman, known to his colleagues as "Magpie", died at the scene after the Jackal off-road vehicle he was driving exploded, the MoD said. Two other soldiers were also injured in the blast.
Trooper Munday's parents, Robert and Caroline Munday, released a statement through the MoD in which they told of their devastation at his death, which brought the number of British service personnel killed in Afghanistan since operations began to 121.
They said: "James was an adventurous, gracious and caring son, who excelled as a soldier and died doing a job he loved.
"James was a tremendous character, who lived life to the full. He was a talented and fearless skier, an enthusiastic horseman and was relishing the opportunity to help those in need on operational service.
"We are devastated by the loss of James, who will be sorely missed by his family, numerous friends and colleagues.
"We are so proud of what he achieved as our son and have been humbled by the many messages of condolences received."
Since training at the Household Cavalry Mounted Regiment in Knightsbridge, he was marked out as a talented jockey and expert downhill skier.
Trooper Munday, a rugby fan, served in Afghanistan after joining the Household Cavalry Regiment, based at Windsor, last year.
Lt Col Fullerton added: "He excelled at all he turned his hand to. He served on this tour with courage, honour, humility and always put his colleagues' interest first. His family have lost a wonderful son and we at the regiment have lost one of the best."