Kate, Britain's Princess of Wales, has been shown looking fit and healthy in the first video taken of her since she underwent surgery two months ago in footage published by the Sun newspaper on its website on Monday.
Kate, 42, spent two weeks in hospital in January after having what her office said was successful, planned surgery for a non-cancerous but unspecified condition.
Other than a couple of blurry pictures, she has not been seen in public since appearing with the other members of the royal family on Christmas Day, and in recent weeks social media has been awash with speculation about her health, generating global headlines and rumours.
In the video, which the Sun said was filmed on Saturday, a smiling Kate is seen, casually dressed, walking and carrying shopping bags alongside her husband, heir to the throne Prince William, at a farm shop in Windsor, near to their home.
"I didn't feel like they were hiding who they were. But they didn't quite know how people would react because there has been this build-up about their whereabouts and I got the sense they just wanted to be swift in there," Nelson Silva, 40, who took the video told the Sun.
"Kate looked happy and relaxed. They look happy just to be able to go to a shop and mingle. Kate looked relieved like it was a success going to a shop. It felt natural."
The couple's office Kensington Palace had no comment on the video. Her spokesperson has said Kate was recovering well but was not expected to return to official duties until after Easter, which falls on March 31.
Her office has also previously asked the media to respect the princess' privacy, and said it would only provide information when there were significant updates. Royal aides do not usually comment on what would be regarded as private time.
The video comes after Kate issued her first public statement earlier this month to thank the public for their messages of support.
However, the next day she apologised for causing confusion by editing an accompanying photo of her and the couple's three children, taken by William, after several leading news organisations, including Reuters, withdrew it saying it did not meet their editorial standards.