A new documentary sheds light on their first meeting.

Queen Elizabeth Prince Philip - LEAD

Some rare details about Queen Elizabeth and Prince Philip's early relationship is coming to light in a new National Geographic documentary.

In a rare recording featured in Being the Queen, Prince Philip's cousin, Lady Pamela Hicks, discussed the moment he and Queen Elizabeth met. Her father, she said, happened to be present when King George VI and the Queen Mother took Elizabeth and her sister Margaret to Dartmouth in 1939.

At the time, Queen Elizabeth (then a Princess) was just about 13 years old and met an 18-year-old Philip, then a cadet and, in Lady Hicks's words, "this absolute Greek god."

"I think the princess fell headlong in love with him at that moment," Lady Hicks says.

Being the Queen also sheds some light on how the couple's relationship developed. According to Robert Lacey, a royal historian, Queen Elizabeth's parents felt "great anxiety" over their daughter wanting to "marry the very first man she falls in love with." After all, it was more than a matter of her personal happiness — the man she married would also "shoulder almost half the burden of the monarchy."

The documentary, directed by Emmy and Peabody Award-winning filmmaker Tom Jennings (who also made the Princess Diana documentary Diana: In Her Own Words) is an intimate look into the Queen's private life and the way it collides with her public-facing role.

Being the Queen airs on National Geographic on August 31 at 9/8p.m. central.