To celebrate 70 years of Queen Elizabeth II’s reign, a new documentary featuring never-before-seen footage of the royal will premiere on May 29.

Entitled “Elizabeth: The Invisible Queen”, the 75-minute BBC television documentary will focus on the early years of Queen Elizabeth’s life, from her birth to her coronation at the age of 27 in 1953. features several Royal Family home recordings, which have until now been privately held in the vaults of the British Film Institute.

Queen Elizabeth granted BBC Studios access to the footage and producers and editors viewed more than 400 film reels. Home recordings include previously lost newsreels and several behind-the-scenes recordings of officially sponsored state events.

According to the BBC, the documentary will feature never-before-seen footage of notable events in the Queen’s life, including Prince Philip’s 1946 visit to Balmoral Castle, shortly before the couple’s engagement became public knowledge. Other major moments that will be depicted in the film include rare captures of the Queen with her uncle Prince George, Duke of Kent, and footage of the Royal Family at Blamoral in 1951, a year before King George died VI. The film will combine the footage with audio news and public speeches from the Queen, instead of traditional narration or interviews.

“We are honored that the Queen has given the BBC such unprecedented access to her personal film collection,” BBC history editor Simon Young said in a statement. “This documentary is an extraordinary insight into a deeply personal side of the royal family that is rarely seen, and it’s wonderful to be able to share it with the nation as we celebrate its platinum jubilee.”

“Elizabeth: The Unseen Queen” is directed by Simon Finch, with Julia Harrington and Harvey Lilley executive producing. Clare Sillery, head of documentary commissioning at the BBC, commissioned the project, while Claire Popplewell served as creative director. BBC Studios produces. The film will be shown on BBC One and BBC iPlayer.