Prince George and Princess Charlotte steal the show - again- at Queen Elizabeth’s 91st birthday celebration

— -- The British royal family celebrated Queen Elizabeth's 91st birthday at the annual Trooping the Colour ceremony in London on Saturday -- but all eyes were on the little Prince George and Princess Charlotte throughout the event.

Once again, the two adorable children of Prince William and Princess Kate stole the show from their famous great grandmother, enthusiastically waving to the crowd and the planes as they streamed above in a red white and blue Royal Air Force flyover.

An excited Prince George and Princess Charlotte could be seen peering out of the Buckingham Palace balcony window before joining great grandmother -- "Gan Gan" -- and the rest of the royal family on the balcony.

Princess Kate was dressed in a pink Alexander McQueen dress and Jane Taylor hat, with Charlotte complementing her mother in a floral pink dress.

A major security operation was underway in the British capital following the recent terror attacks in London and Manchester. Snipers were positioned on roofs, with additional security forces on duty and plainclothes officers blending in with the public, as every senior member of the royal family participated in the queen’s official birthday celebration.

The annual Trooping the Colour ceremony took a more somber tone this morning, with a moment of silence and Queen Elizabeth issuing a special message one day after she and Prince William visited the survivors of the Grenfell Tower fire, and just weeks after the terror attacks in London and Manchester. At least 30 people died in the West London fire, with more fatalities expected to be announced.

"Today is traditionally a day of celebration. This year, however, it is difficult to escape a very sombre national mood." The Buckingham Palace statement issued by Queen Elizabeth said: "In recent months, the country has witnessed a succession of terrible tragedies. As a nation, we continue to reflect and pray for all those who have been directly affected by these events."

With Prince Philip recently announcing his retirement, this may be one of the last events the Duke of Edinburgh will play such a prominent role. Queen Elizabeth and Prince Philip's carriage led the procession with Prince Harry, Princess Kate and Camilla, The Duchess of Cornwall, following in the second carriage.

Prince William, Royal colonel of the Irish Guards, and Prince Charles rode on horseback with their regiments.

Trooping the Colour dates back to 1748 started by King George II, whose birthday was in November. A decision was made to have an official birthday celebration for the monarch's birthday during a warmer weather season. Queen Elizabeth's actual birthday is April 21.

More than 1400 troops and 200 horses took part in the procession, with the monarch inspecting the troops and taking the salute at Horseguards Parade before returning back to Buckingham Place, where the royal family joined Queen Elizabeth on the balcony for the Royal Air Force flypast.

This year’s Trooping the Colour took on special significance, as the country mourned those who recently died and celebrated the heroism of others.

“During recent visits in Manchester and London, I have been profoundly struck by the immediate inclination of people throughout the country to offer comfort and support to those in desperate need,” Queen Elizabeth wrote in her message.

Today, the country showed their resilience and paid tribute to their beloved monarch, but also to all of those affected by the terror attacks and the Grenfell Tower fire.