The Duke and Duchess of Sussex have appeared as part of an emotionally-charged trailer for Harry’s mental health documentary series with Oprah Winfrey.

Harry says in conversation with Winfrey: “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.”

Footage of a young Harry during his late mother Diana, Princess of Wales’s funeral procession features in the 2.28-minute trailer, which was released on the Archewell website.

The archive film shows Harry standing with his head bowed as his mother’s coffin passes by, and alongside the Prince of Wales as Charles turns to speak to his 12-year-old son.

The trailer for The Me You Can’t See was released just days after Harry appeared to suggest that his father and the Queen and the Duke of Edinburgh had failed as parents, while the family is still mourning Philip.

Speaking on the Armchair Expert podcast, the duke said he wanted to “break the cycle” of “genetic pain and suffering” for the sake of his own children.

He said of Charles: “He’s treated me the way he was treated, so how can I change that for my own kids?”

The Apple TV+ series will begin on Friday May 21 and singer Lady Gaga, actress Glenn Close, Syrian refugee Fawzi, and DeMar DeRozan of the NBA’s San Antonio Spurs, all appear in the trailer.

Lady Gaga and Glenn Close, along with Winfrey, appear close to tears as they discuss their experiences.

At one point, Harry is seen taking a deep breath as he prepares to speak.

After a sequence where other contributors appear tearful, Harry is seen looking serious and thoughtful as he holds his hand to his mouth.

Winfrey says: “It’s just something I accepted.”

Meghan makes a brief appearance, coming into shot at Harry’s side.

The duchess is smiling and wearing a T-shirt printed with the slogan “Raising the Future”, and belted black trousers with no sign then of a baby bump.

The duchess is now heavily pregnant with the couple’s second child – a daughter.

The Sussexes’ son Archie is also shown sitting on his mother’s lap later on – in footage filmed around the time of his first birthday.

The duke and Winfrey have joined forces to guide “honest discussions about mental health and emotional wellbeing while opening up about their personal journeys and struggles”, the Archewell website said.

They are seen discussing the language used around mental health.

Winfrey says: “All over the world people are in some kind of mental, psychological, emotional pain.”

Harry asks: “What words have you heard around mental health? Crazy?”

Winfrey replies: “Lost it. Can’t keep it together … It’s that stigma of being labelled ‘the other’.”

Harry also says: “The results of this year will be felt for decades. The kids, families, husbands, wives, everybody.”

Harry and Winfrey are co-creators and executive producers of the project.

The Sussexes made a series of damaging allegations about the royal family when they were interviewed by Winfrey earlier his year.

The couple accused an unnamed royal, not the Queen or Philip, of raising concerns about how dark their son Archie’s skin tone would be, before he was born.

Meghan also said she asked for help when she was suicidal, but said the monarchy gave her no support.

Harry has spoken of the emotional turmoil he faced after his mother was killed in a Paris car crash in 1997, saying he spent nearly two decades “not thinking” about her death before eventually getting help after a period of “total chaos”.

The series has been directed by acclaimed filmmakers Dawn Porter and Asif Kapadia.