Why Kate's personal video marks strikingly different approach

Such a personal video is a strikingly different approach for a health update about the Princess of Wales.

It is highly emotional and full of harvest colours heading into an almost melancholy tone, as Catherine walks in the countryside with her family.

There could have been a traditional press release, or a statement delivered to the camera, but instead there's a soft focus, cinematic touch to this message.

Instead of footnotes and explainers about the completion of her chemotherapy, there's stylised filming and an intimate first-person narration.

The video was filmed last month in Norfolk

This is clearly a well-planned approach to releasing information, with the filming by Will Warr taking place in Norfolk last month, and the changes of clothes suggesting more than one filming session.

It's a world away from old school royal releases which stuck to the barest of details and stayed as dry as the desert.

This much lusher treatment follows the trend of celebrities and public figures taking their messages straight to the public, using the language of social media rather than conventional news or an interview.

It allows a great deal of control over the message - with evocative music and slick editing driving the story forward, rather than any questions that might arise about her health or treatment.

We see Catherine, in a 1970s-style long flowing dress, spending time with her family in the woods and by the beach, playing a game with her own parents.

These are framed in a relatable way - a family relaxing after really tough times, in a rural setting that's meant to send a message about the soothing powers of nature.

Over the top of the pictures is Catherine's narration, in a movie voiceover style, capturing her sense of cautious optimism, as she welcomes the end of her chemotherapy while at the same time recognising the fragility of life.

It's where Norfolk meets Hollywood plus Instagram.

The personal video has a retro feel in parts

There's almost an echo of a film such as About Time in the video, with its melancholy music, sad themes and a life-affirming narration about how a family can be changed forever by unexpected events.

The comparisons are with movie styles and flashback sequences, rather than news releases.

There's also clearly an awareness of how this short film might be seen by the many families facing cancer in their own lives. It's a sensitivity that seems close to the surface.

It almost becomes a prayer at the end, with the invocation: "To all those who are continuing their own cancer journey - I remain with you, side by side, hand in hand. Out of darkness, can come light, so let that light shine bright."