Britain's Queen Elizabeth II did not attend a church service on Friday after experiencing "some discomfort" during the first day of the Platinum Jubilee celebrations, which marks her 70th year on the throne, Buckingham Palace said.

The Palace later confirmed the queen would also miss Saturday's 243rd Epsom Derby, which she normally attends. The prestigious horse race will be the focal point of the third day of Jubilee celebrations, together with a pop concert outside Buckingham Palace. 

As with the service, she will watch the Derby on television.

Queen Elizabeth, who ascended to the throne in February 1952 after the death of her father, is the longest-serving British monarch. In April, the queen turned 96-years-old.

What happened Friday during the Jubilee?

UK Prime Minister Boris Johnson was met with boos and jeers when he arrived at St. Paul's Cathedral with wife Carrie for the service of thanksgiving. Others in the crowd responded to the audible sound of displeasure with the prime minister with cheers and applause.

Prince Harry and Meghan Markle also attended the church service Friday, entering the church together holding hands and walking down the long hall of the cathedral ahead of other senior royals. Many in the crowd turned to watch the pair, who abandoned royal duties two years ago in favor of life in California.

The queen, Buckingham Palace said in a statement late Thursday, had to "reluctantly" pull out of Friday's celebrations.

"Taking into account the journey and activity required to participate in tomorrow's national service of thanksgiving at St Paul's Cathedral, Her Majesty with great reluctance has concluded that she will not attend," the statement read.

Prince Andrew, the Duke of York, was also not present at the church service because he tested positive for COVID-19 earlier this week. 

The queen thanked the British people in a written message, saying she continued to "be inspired by the goodwill shown to me…as we look to the future with confidence and enthusiasm."

Platinum celebrations kick off

Thousands of people flocked in front of Buckingham Palace in London on June 2, which marked the first of a four-day celebration to honor the queen's seven-decade rule.

The queen kicked things off by taking part in the annual Trooping the Color event, a military parade that takes place annually in June to celebrate Britain's sovereigns.

She also appeared on the famous balcony of the Buckingham Palace after the parade to greet a sea of cheering supporters. Along with other members of the Royal Family, the queen then observed a flypast from the balcony.

Later in the evening, the queen took part in a beacon lighting ceremony, despite not feeling well.

The Buckingham Palace said in its statement Thursday that the queen "greatly enjoyed today’s birthday parade and flypast."

It is not fully clear whether health complications will impact her attendance in other events planned through the weekend, though her health has been a matter of concern recently.

Prince Harry and Meghan, the Duke and Duchess of Sussex, who flew over from California, watched the queen's birthday parade on Thursday. They maintained a low-key presence through Thursday's Jubilee events, and are expected to attend the church service Friday.

rm/rs (AP, Reuters)