The King missed church on Sunday as he prepares to go to hospital for an operation this week.
Charles is regularly seen walking to the church service at St Mary Magdalene Church when he stays at the Sandringham estate in Norfolk, but this week he could not attend.
The King and Queen retuned to Sandringham Estate on Friday from Scotland ahead of his surgery for an enlarged prostate.
The couple travelled on an RAF jet from Aberdeen Airport to RAF Marham and were driven the rest of the journey to Sandringham.
King Charles attends the Sunday service at the Church of St Mary Magdalene on January 7 2023.
Well-wishers waited outside the church on Sunday hoping to catch sight of the King, but they found the gates to the paddock outside the church were locked.
Usually, onlookers are allowed to watch the King walk to church from the roped-off path on the Sandringham Estate.
Victoria Martin, 67 a holidaymaker from Rye, East Sussex said: “It’s a shame we haven’t seen him, but it’s understandable if he wants to keep quiet before going into hospital.”
Another well-wisher said: “I was a little disappointed that he didn’t come because I wanted to wish him the best of luck for his surgery.”
Charles and Camilla attend New Year’s Eve church service.
Another person noted how it was “highly unusual” to find the gates to the church paddocks locked.
King Charles attended the church service at St Mary Magdalene on the Sandringham Estate in Norfolk on New Year’s Eve in December 2023 where he was pictured waving to onlookers.
The Sovereign has a close relationship with the church and is titled “Defender of the Faith and Supreme Governor of the Church of England.”
The Queen said the King was “fine” and “looking forward to getting back to work” after her visit to the Aberdeen Art Gallery last week.
The King is set to attend hospital for surgery next week.
The King travelled from Scotland to England on Friday in an RAF jet.
Last week Buckingham Palace announced the King’s condition shortly after Kensington Palace revealed that Kate had undergone abdominal surgery.
The statement read: “In common with thousands of men each year, the king has sought treatment for an enlarged prostate
“His Majesty’s condition is benign and he will attend hospital next week for a corrective procedure. The king’s public engagements will be postponed for a short period of recuperation.”
Charles wanted to share the news with the public to encourage men who may experience similar symptoms to get checked.
Kate is recovering at The London Clinic, a private and well renowned hospital in central London.