During the final years of Princess Diana's marriage to Prince Charles, the popular royal wasted no opportunity to tell the world that their union was far from happy, experts claimed. While the royal couple attended events together, Diana made it no secret that their marriage was already in the rocks.

According to Princess Diana's long-time aide Paul Burrell, the well-loved princess did not have a true voice when it comes to royal affairs, but she made sure that she was still able to communicate to the world that she and Prince Charles were no longer in good terms, reported Express UK.

"I think Diana was very clever. She didn't have a true voice, but she was able to convert her feelings in pictures," Burrell said about Princess Diana's subtle hints about their marital troubles.

Burrell, who was a butler for the princess until her death, was able to observe the actual events as they unfolded in the royal household. He recalled that Princess Diana hinted at her loneliness with one photograph during her tour in India where she was pictured alone as she took on the view of the Taj Mahal.

This was very significant given the story behind the world-renowned site. The structure was commissioner by 1632 by Shah Jahan to house the tomb of his most beloved wife Mumtaz Mahal, which was a direct contrast to the state of the Princess' marriage to Prince Charles.

According to The Evening Standard royal editor Robert Jobson, the final clue that the marriage was falling apart was most evident during the royal tour to South Korea in 1992, which took place a month before they announced their separation in December.

"I remember being on a visit to Korea, and it was very, very clear then that the marriage was over. She was doing her best to upstage the prince at every opportunity," he recalled.

The royal expert said that Princess Diana shunned protocol at official events and breezed through the dignitaries as her then-husband shook hands and exchanged pleasantries with diplomats and officials in a bid to embarrass him. This was a far cry from Princess Diana that the world knew since the princess fulfilled her royal duties responsibly while she was married to the Prince of Wales.

Former royal press secretary Dickie Arbiter agreed that Princess Diana made her displeasure over the marriage clear with her body language and actions. By the time the royal tour reached South Korea, it was no secret that the marriage was over, he admitted.