Princess Diana, Prince William, Harry and Charles
Princess Diana received a kiss from Prince William and bickered with Prince Charles in a documentary that has since resurfaced. Pictured: Princess Diana, Prince Harry, Prince William and Prince Charles watch the parade march past as part of the commemorations of VJ Day on Aug. 19, 1995 in London. Getty Images/Johnny Eggitt

One of Princess Diana and Prince William's most adorable moments was caught on camera.

An archive footage of the documentary "Charles and Di: In. Private and Public" has resurfaced. Express shared some clips from the documentary, and one scene featured a sweet moment between Prince William and mom Princess Diana.

The Duke of Cambridge, who was only 5 years old at the time, was keen to sit in the helicopter that arrived to pick up the Prince of Wales. Prince William and Prince Harry were helped up into the aircraft.

When Prince William was seated comfortably, Princess Diana leaned on the side of the helicopter to watch her children inside the aircraft. Then Prince William leaned out of the window and to kiss his mom on the nose. The late Princess of Wales smiled after receiving a sweet gesture from her son.

The clip also showed Prince Charles pointing towards Prince Harry who was seated on the pilot's lap. "Gosh, future helicopter pilot, without a doubt," the Prince of Wales said.

In another scene, Princess Diana and Prince Charles can be seen bickering over their schedules. The Prince and Princess of Wales agreed to prioritize their engagements as they couldn't fit them all into their schedule.

Prince Charles set a basic timetable of the events he wanted to attend. Princess Diana also made her own list and they ended up in a minor argument when they began discussing.

Prince Charles was unsure if Princess Diana would join him at the Royal College of Music because the latter was a patron of the rival Royal Academy of Music. Princess Diana said that she's coming. The future kings was ecstatic and cheekily poked his then-wife's left side. Princess Diana rejected his advances and lifted her arm and pushed his hand away.

In related news, Princess Diana made a shocking confession about her sex life with Prince Charles. Given that they were a couple, she admitted that they also had intimate moments, but she found it "odd."

"Well there was [sex.] There was. There was. But it was odd, very odd," Princess Diana said. "But it was there then it fizzled out about seven years ago, six years ago, well seven, because Harry was 8."