The Prince of Wales and Duke of Sussex have joined their cousins in a solemn vigil at their beloved grandmother’s coffin.

Brothers William and Harry - both dressed in uniform - stood guard at the Queen’s lying in state in Westminster Hall on Saturday evening as a stream of mourners filed past after queueing for hours.

WATCH THE VIDEO ABOVE: Queen’s grandchildren hold powerful vigil

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Harry, who saw action on the front line during two tours of duty in Afghanistan, has previously been denied the chance to wear his military uniform as he publicly mourns, because he is no longer a working royal.

But royal sources said the King decided his youngest son could wear uniform for the vigil.

Despite being a former Army officer, Harry has been in civilian dress for official events, including walking behind the Queen’s coffin on Wednesday.

William and Harry were joined in their silent tribute around the coffin by cousins Zara Tindall and Peter Phillips, Princesses Beatrice and Eugenie, and Lady Louise Windsor and her brother Viscount Severn.

On Friday evening, the Queen’s children - Charles, the Duke of York, the Princess Royal and the Earl of Wessex - took part in their own vigil.

They were all dressed in uniform, with an exception made for disgraced Andrew, who is no longer a working royal, to wear his military uniform as a “special mark of respect” for the Queen.

Royal princesses miss their ‘grannie’

Princesses Beatrice and Eugenie issued a tribute to their “dearest grannie”, saying how much they missed the late Queen Elizabeth and had thought she would be around forever.

“We’ve not been able to put much into words since you left us all,” said the two princesses, the daughters of Prince Andrew, the queen’s second son and Duke of York.

“There have been tears and laughter, silences and chatter, hugs and loneliness, and a collective loss for you, our beloved queen and our beloved grannie.”

Beatrice, 34, and Eugenie, 32, will join their cousins later on Saturday for a vigil by the coffin of Elizabeth at Westminster Hall where the body of the late monarch is now lying in state.

Eugenie was seen wiping away tears when she appeared in the days immediately after her grandmother’s death when members of the family read tributes outside Balmoral Castle where Elizabeth died on September 8 aged 96.

“We, like many, thought you’d be here forever. And we all miss you terribly,” the sisters said in a statement.

“You were our matriarch, our guide, our loving hand on our backs leading us through this world. You taught us so much and we will cherish those lessons and memories forever. For now dear grannie, all we want to say is thank you.”

The two royals concluded their message by saying the tributes that had flooded in from across the world as it mourned her would have made their grandmother smile.

“We’re so happy you’re back with grandpa,” they said, a reference to Elizabeth’s late husband Prince Philip, who died last year.

“Goodbye dear grannie, it has been the honour of our lives to have been your granddaughters and we’re so very proud of you. We know that dear Uncle Charles, the king, will continue to lead in your example as he too has dedicated his life to service.”