The documentary series, made in collaboration with US talk show host Oprah Winfrey, is expected to feature Harry, 36, reliving on screen the trauma of the death of his mother, Diana, Princess of Wales in 1997.
The prince, who quit working as a full-time royal last year and now lives in California, has been critical of the monarchy in recent interviews.
His new docuseries, called The Me You Can’t See, begins on Friday on Apple TV+. Harry and Winfrey produced the series, which has been shot by Bafta award-winning director Asif Kapadia.
A trailer for the series was released on Monday. It featured archive footage of Harry, aged 12, at his mother’s funeral. He has previously said that walking behind her coffin was something no child “should be asked to do”.
Palace aides fear the full series could feature further criticism from Harry about his upbringing.
Harry’s wife, Meghan, makes two short appearances in the trailer. In one, she stands behind her husband wearing a statement T-shirt reading “raising the future.” In the other, she is seen reading to the couple’s son, Archie in footage released for his first birthday. He is now two.
The series also features celebrities talking about their mental health, including Lady Gaga, actress Glenn Close and DeMar DeRozan of the NBA’s San Antonio Spurs.
Lady Gaga said she wanted to share her story as: “I have been through it and people need help.” In the trailer, Harry says: “To make that decision to receive help is not a sign of weakness, In today’s world, more than ever, it is a sign of strength.”