LONDON: Queen Elizabeth II is celebrating her birthday with traditional pomp and circumstance — but without her husband by her side.

Prince Philip remains in the hospital, recovering from exploratory abdominal surgery.

The queen invited her cousin, the Duke of Kent, to accompany her in a vintage carriage. Other royals — including Prince Harry and the Duchess of Cambridge — joined in the celebration Saturday.

More than 1,000 soldiers, horses and musicians are taking part in the parade known as "Trooping the Color," an annual ceremony marking the queen's official birthday.

The monarch's actual birthday was on April 21, when she turned 87.

The ceremony originates from traditional battle preparations, when "colors," which refer to military flags, were carried down the rank to be seen by soldiers.