"I found it very overwhelming." Prince William reflects on the death of Princess Diana.

To catch up on all things royal family, make sure you check out our Royal Hub. We’ve got you completely covered.

In a rare, personal interview, Prince William has opened up the death of his mother, Princess Diana.

In upcoming documentary, Football, Prince William and Our Mental Health, the Duke of Cambridge opened up about how becoming a father brought back emotions he felt after his mother passed away.

While speaking to former professional footballer Marvin Sordell, who grew up without a father, William reflected on becoming a father without the support of his own mother.

Watch the trailer for Football, Prince William and Our Mental Health below. Post continues after video.

“Having children is the biggest life-changing moment, it really is,” he said.

“I think when you’ve been through something traumatic in life – and that is like you say your dad not being around, my mother dying when I was younger – your emotions come back in leaps and bounds because it’s a very different phase of life,” he continued.

“And there’s no one there to kind of, help you, and I definitely found it very, at times, overwhelming.”

William added that he and his wife Kate “support each other” and work as a team to raise their kids.

“I think emotionally, things come out of the blue that you don’t ever expect or maybe you think you’ve dealt with and so I can completely relate to what you’re saying about children coming alone, it’s one of the most amazing moments of life but it’s also one of the scariest.”

The Duke and Duchess of Cambridge have three children together – six-year-old Prince George, five-year-old Princess Charlotte, and two-year-old Prince Louis.

Prince William’s mother, Princess Diana, died in 1997, when William was 15 years old. William’s younger brother, Prince Harry, was 12 years old.

In recent years, Prince William has spoken on occasion about his relationship with his mother, and how he coped with her passing.

Listen to Mamamia Out Loud, Mamamia’s podcast with what women are talking about this week. Post continues below.

Speaking in BBC documentary A Royal Team Talk in 2019, William described losing his mother as a “pain like no other”.

“I think when you are bereaved at a very young… you feel pain like no other pain,” he said.

“And you know that in your life it’s going to be very difficult to come across something that’s going to be an even worse pain than that.”

The 37-year-old also shared that he still struggles with the shock of her death.

“I still feel, you know, 20 years later about my mother, I still have shock within me,” he shared.

From a young age, William was known for being fiercely protective of his mother.

When Diana and Prince Charles separated, William, just a teenager, helped his mum through the ordeal, with Diana “relying on her eldest son for comfort and advice”.

"It's believed that William later advised [Diana] to accelerate her divorce proceedings by agreeing to be stripped of her royal title," the narrator said in documentary, Prince William: Royalty In My Family.

Prince William reportedly told Diana: "You'll still be my mummy."

In the same documentary, it's reported that William booked a reservation at his mother's favourite restaurant when he was nine years old in the hopes of cheering her up.

According to Her, William even looked into becoming a police officer, in the hopes of protecting his mum.

Last year, William reflected on what Diana would have been like as a grandmother to his three children.

"She'd be a nightmare grandmother – absolute nightmare. She'd love the children to bits, but she'd be an absolute nightmare," he joked.

"She'd come and go and she'd come in probably at bath time, cause an amazing amount of scene, bubbles everywhere, bathwater all over the place, and then leave."

The Duke of Cambridge also shared that he often speaks to his children about his mother.

"We've got more photos up round the house now of her and we talk about her a bit and stuff. It's hard, because obviously Catherine didn't know her, so she cannot really provide that, that level of detail. So, I do regularly when putting George or Charlotte to bed, talk about her and just try and remind them that there are two grandmothers – there were two grandmothers – in their lives," William said.

"It's important that they know who she was and that she existed."

Feature Image: Getty.

Sign up for the "Mamamia Daily" newsletter. Get across the stories women are talking about today.