Princess Diana: My Sister’s Story (2026): Cast, Story and Release

Prepared by Movies Dock Editorial

Princess Diana: My Sister’s Story is a 29-minute UK documentary built around Laura Kuenssberg’s interview with Charles Spencer. The conversation concerns new revelations in Spencer’s latest book and reflects on Diana’s marriage, death and enduring impact on Princes William and Harry, using a direct interview format.

Princess Diana: My Sister’s Story is a short documentary centered on a conversation between journalist Laura Kuenssberg and Charles Spencer, Diana, Princess of Wales’s brother. The programme focuses on revelations connected to Spencer’s latest book.

With a runtime of 29 minutes, the film takes a focused interview-based approach to subjects including Diana’s marriage to the now King, her tragic death and the continuing effect of her life and legacy on her children, Princes William and Harry.

Princess Diana: My Sister’s Story movie details

Story without spoilers

The documentary presents Laura Kuenssberg interviewing Earl Spencer after new revelations in his latest book about his sister, Diana, Princess of Wales. Its subject matter includes Diana’s marriage to the now King, her death and the lasting impact of those events on Princes William and Harry.

Rather than following a fictional storyline, the film is structured around first-person discussion and the perspective of a close family member. The supplied information identifies it as a UK exclusive, with the interview serving as its central format.

What to expect

Viewers can expect a concise documentary built around an interview rather than a dramatized reconstruction. Its focus is the British royal family, especially Charles Spencer’s account of matters connected to Diana and the revelations associated with his book.

At 29 minutes, the film offers a compact treatment of its subject. The available details point to a serious, conversation-led presentation addressing public and family history without indicating additional contributors, reenactments or a broader production format.

Cast and creative team

Laura Kuenssberg appears as herself and conducts the interview. Charles Spencer also appears as himself, sharing the perspective at the center of the documentary. No director or writer is listed in the supplied credits.

• Laura Kuenssberg as Self
• Charles Spencer as Self

Release and production context

Princess Diana: My Sister’s Story is a 2026 documentary from the United Kingdom. It has a listed release date of September 20, 2026, a runtime of 29 minutes and English as its spoken language. The supplied metadata lists the film’s status as Released and does not identify a production company.

Movies Dock view

Princess Diana: My Sister’s Story is a brief, interview-led documentary for viewers interested in Diana, Princess of Wales, Charles Spencer’s perspective and the continuing public significance of the royal family’s history. Its concise runtime keeps the focus on the conversation and the book revelations described in the synopsis.

Film data:
TMDB