Prince William was commissioned as an officer in the British Army on Friday as his grandmother, Queen Elizabeth II, served as the reviewing officer.

"This is a milestone day... which will stay forever in your minds," the 80-year-old monarch, dressed in a red hat and coat, told the cadets.

"You must be courageous yet selfless, leaders yet carers, confident yet considerate. ... These are very special attributes, but those whom you will command and your country too will expect nothing less. My prayer for your success and safety will follow you wherever you happen to serve.''

The Queen has previously acted as the reviewing officer in 1949, 1965, 1985 and 1991. Of course, her return was of no coincidence.

"I think besides being the Queen, she is a woman, she is a grandmother and she's proud of him," Dr. Brian McKercher, a history professor at Canada's Royal Military College, told CTV.ca.

Prince Harry, who graduated in April from the Royal Military Academy Sandhurst (RMAS), and William are both assigned to the Blues and Royals regiment of the Household Cavalry.

To graduate, William had to complete the 44-week commissioning course.

He is now formally known as 2nd Lieutenant William Wales and will train to be a troop commander in an armoured reconnaissance unit. However, he will probably never see front line action.

"He'll go into a regiment for sure but he'll not go into danger... he's the heir to the throne," said McKercher.

After a year in the army, William will then spend time on "familiarization attachments" in the Royal Air Force and Royal Navy.

William's father, Prince Charles, was also in attendance and took the salute.

The focus was also on William's girlfriend, Kate Middleton, who wore a bright scarlet coat and a dark hat.

It was the first time Middleton appeared at such a high-profile event with members of the House of Windsor.

Rumours continue to swirl about possible marriage plans between Middleton and the 24-year-old future king.

The original Royal Military Academy (RMA) was first established at Woolwich in 1741 for the training of Artillery and Engineer officers. Cavalry and Infantry officers were trained at the Royal Military College (RMC).

The RMC moved to Sandhurst in 1812 and merged with the RMA after the Second World War forming the current RMAS.

The event comes just one day after a British police report that concluded that William's mother, Princess Diana, died from a 'tragic accident' and not from a murder conspiracy plot.