CNN announced this afternoon that it will premiere “CNN: Special Investigations Unit - Growing Up Diana” with Soledad O’Brien on Saturday, August 25th at 8pm ET…

As the 10th anniversary of Princess Diana’s tragic death approaches, CNN’s Soledad O’Brien reports an intimate portrait of the early years of the Princess of Wales. CNN: Special Investigations Unit - Growing Up Diana begins with her years growing up in the shadow of royalty and ends as her marriage approached troubled times, almost as it began. Growing Up Diana premieres on Tuesday, Aug. 21, at 8 p.m., and replays on Saturday, Aug. 25, and Sunday, Aug. 26, at 8 p.m. and 11 p.m. All times Eastern.

O’Brien takes viewers on location to explore Diana’s childhood home, the place where she met Prince Charles, and the roots of her insecurities – all revealed through the words of people who knew her first hand, some of whom have never spoken previously.

The documentary features exclusive interviews including one with Inga Crane, Diana’s childhood au pair, and a 2001 CNN interview with Diana’s brother, Lord Charles Spencer. It also includes rare interviews with Robert Spencer, Diana’s cousin; Mary Clarke, Diana’s childhood nanny; Penny Walker, Diana’s former music teacher; James Colthurst, Diana’s close friend and confidante; and Mary Robertson, an American expatriate for whom Diana worked as a nanny. Robertson gives CNN viewers a first-ever look at Diana’s personal correspondence to her, revealing personal stories of a very public woman.

Despite being born into a family of extraordinary privilege, the young Diana Spencer did not have the happiest of childhoods. Born the third girl into titled British aristocracy, Diana may have felt she was an unwanted child. The documentary reveals that early feelings of inadequacy and need for approval may have instilled emotional insecurities that followed Diana into her adult life.

Her parents’ bitter divorce and custody battle left psychological wounds. Mary Clarke recalls a young Diana making a precocious declaration about divorce during their first meeting: “She said, ‘I will never marry unless I’m really in love, because if you’re not in love, you’re going to get divorced, and I never intend to get divorced.’”

Penny Walker, who taught Diana at West Heath School for Girls, describes her as distracted by her family troubles, which grew even more complicated when her father began dating and later suffered a stroke. Walker said Diana seemed to find solace in music, swimming and, notably, volunteer service. Walker also remembered that at age 13, Diana had an intense crush on Prince Charles, instead of the usual pop stars her friends idolized.

The documentary takes viewers through the courtship of Diana and Prince Charles, noting that they first met when she was just 16 years old and began dating in secret when she was 18. Charles was 31. Despite being hounded by reporters when news broke of their relationship, Diana was careful to stay silent until the engagement was announced.

O’Brien takes viewers behind the scenes of the most watched wedding of all time – more than 750 million people worldwide tuned in – with insiders at Diana’s side including one of her bridesmaids, her wedding gown designer and a close friend who says Diana almost canceled the wedding at the last minute.

Although the marriage was ultimately ill-fated, her friends recall Diana as a warm, loving woman who adored her children, invested time and compassion into causes such as land mines and HIV/AIDS, and ultimately changed the face of the modern monarchy. Essential to that legacy are her two sons who have followed in her philanthropic footsteps and recently gave a benefit concert in support of her favorite charities.

Growing Up Diana is produced by Melissa Dunst Lipman and edited by Ross Helman. Bud Bultman is the managing editor. Mark Nelson is the vice president and senior executive producer of CNN Productions.