Prince Harry has said one of his son’s first words was “grandma”, as he spoke of his sadness that his mother was not around to see him become a father.

Speaking in the fifth episode of Apple TV’s The Me You Can’t See, his mental health documentary series with Oprah Winfrey, Harry told of being “really sad” that Diana, Princess of Wales, could not be there to meet Archie.

Harry said Archie learned the word “grandma” because of a picture of his mother in the nursery at their home in Los Angeles.

The series showed new footage of Harry playing with his toddler son on a beach and on some swings. Another clip saw Meghan and Archie reading a book together and laughing.

Harry said: “We’ve got a beautiful little boy who keeps us busy, who keeps us running around. He makes us laugh every day which is great. We [have] got two dogs and then another little baby girl on the way, I never dreamt that.”

Harry said that he had “no doubt” his mother Diana would be “incredibly proud” of him for living the life she would have wanted.

He was just 12 when she died in August 1997 in a car crash while being pursued by the press in Paris. He went on to say: “I wish she could have met Meghan, I wish she was around for Archie.

“I got a photo up in his nursery and it was one of the first words that he said, apart from ‘mama’, ‘papa’ it was then ‘grandma’ – Grandma Diana.

“It’s the sweetest thing, but at the same time it makes me really sad, because she should be here.”

The documentary series focuses on mental illness to inspire viewers to have an honest conversation about the challenges people face.