The Duke of Edinburgh was absent from this year's Easter service at Windsor attended by the Queen.
Philip, who has effectively retired from royal duties, was absent from the Easter Mattins Service at St George's Chapel, Windsor Castle - where Prince Harry will marry Meghan Markle in May.
It is understood he was not due to attend the service.
The church service is the latest event the 96-year-old duke has been absent from in recent days and it is understood that he has been experiencing some trouble with his hip.
The Queen was joined by members of the royal family including the Duke and Duchess of Cambridge, who were there without their children.
William and Kate were the final royals to arrive at the church - arriving after the Queen and other family members had already gone in - and a few minutes after the 10.45am start time.
Kate looked elegant in a classic dark coat and matching hat as she made her way into the 14th-century Gothic chapel inside the castle walls.
The Duchess, who is expected to give birth to her third child this month, is now on maternity leave.
Harry and Meghan were not at the service, with Kensington Palace describing their weekend plans as "private".
Members of the public waited outside the chapel as the 91-year-old monarch arrived.
Prince Andrew and his daughters Princess Beatrice and Princess Eugenie attended the Easter service, along with Eugenie's fiance Jack Brooksbank.
The Princess Royal and her husband Vice Admiral Sir Timothy Laurence led the royal family down the hill to the chapel, and were joined by Zara Tindall.
Princess Anne's son Peter Phillips and his wife Autumn, Prince Edward, the Countess of Wessex and their children Lady Louise Windsor and James, Viscount Severn, also attended the service.
It is understood Philip missed the annual Maundy Service on Thursday because of a problem with his hip.
It is not thought to be a serious issue as Philip, who was named as a guest in the order of service for the Maundy Thursday event, was spotted driving in Windsor Great Park on Wednesday.
Last week, Philip pulled out of an official engagement with the Queen and Duke of York because he was unwell, according to reports.
He was due to attend an event at Windsor Castle to mark Andrew's new role as Colonel of the Grenadier Guards but was unable to attend because he was feeling "under the weather", the Daily Mail reported.
He stepped down from his public duties last summer but on occasion does attend events with the Queen.
When it was announced last year that he would be retiring from official engagements, Buckingham Palace stressed that the decision was not health-related and he had the full support of the Queen.