Key Takeaways:

• Gun salutes will be fired in honour of Queen Elizabeth II's 96th birthday on Thursday, although the monarch is expected to celebrate quietly.
• The king has had a second formal birthday since the 18th century, traditionally celebrated in June when the weather is good.
• Her grandson Prince Harry told US station NBC on Wednesday that she was "in excellent form" when he met her last week in an interview that aired on Wednesday.

On Thursday, gun salutes will be fired to commemorate Queen Elizabeth II's 96th birthday, while the monarch herself is expected to celebrate quietly.

The royal family of the United Kingdom has had a difficult year, with fears about the queen's health and uncertainties about the monarchy's future.

In the British capital, rounds will be fired from the Tower of London and Hyde Park, where a military band will perform "Happy Birthday."

Since the 18th century, the monarch has had a second official birthday, usually celebrated in June when the weather is nicer.

The queen's official birthday falls on June 2-5, and there will be four days of public activities to commemorate her record-breaking 70th year on the throne.

According to British media, the queen flew by helicopter from her Windsor Castle home west of London to her Sandringham country estate in eastern England.

She is visiting the property where her late husband, Prince Philip, lived after he retired from public life in 2017.

According to the Daily Mirror, given the queen's recent health concerns, the trip is being considered a "good move," according to an unnamed royal insider.

She has drastically reduced her public appearances on doctor's orders since an unplanned overnight stay in the hospital last October.

She has had to cancel several commitments due to back pain and difficulty standing and walking, including recent church Easter activities.

During a virtual event earlier this month, she informed doctors and patients at the Royal London Hospital that about of Covid-19 in February left her "extremely tired and exhausted."

In an interview aired on Wednesday, her grandson Prince Harry told US channel NBC that she was "in the terrific form" when he met her last week.

The queen was last seen in public on March 29 at a memorial service for Prince Philip, who died last year at 99 at Westminster Abbey in central London.