Author Sally Bedell Smith can distinctly remember the first time she met Prince Charles. She was attending a polo match with some friends in England in 1991. One of her friends had a close relationship with the princeā€™s grandmother, the Queen Mother, and the future king came over to greet her.

ā€œHe ran up to her and kissed her,ā€ Bedell Smith recalled to CTVā€™s Your Morning on Monday. ā€œHe was so warm to her and informal and casual. I thought, ā€˜This is not the buttoned-up old fogey that is his prevailing image.ā€™ā€

The unexpected encounter with the Prince of Wales piqued Bedell Smithā€™s curiosity about the true nature of the heir to the throne. After writing books about the lives of Charlesā€™ former wife Princess Diana and his mother Queen Elizabeth II, the royal-watcher has revisited those lingering questions about the future king in her newest book ā€“ ā€œPrince Charles: The Passions and Paradox of an Improbable Life.ā€

ā€˜The charitable entrepreneurā€™

Bedell Smith spent approximately four years researching and conducting interviews with more than 300 sources familiar with Prince Charles for the biography.

From his seemingly endless charitable endeavours to his concern for the effects of climate change to his yearning for spiritual enlightenment, the author said she was amazed to learn about the princeā€™s diverse range of interests.

ā€œThe big surprise to me was the amazing legacy he will leave as Prince of Wales, the role he created for himself along the way,ā€ she told Ā鶹“«Ć½ Channel. ā€œPrince Charles has made a real impact.ā€

The biographer said the most difficult part about the project was lacing together the different sides to the princeā€™s personality and his varied pursuits.

ā€œThat was the challenge,ā€ Bedell Smith said. ā€œGetting my arms around this sprawling life and tracing the threads of his thinking.ā€

A life overshadowed:

Since he was three years old, Prince Charles has been waiting in the wings to become King. As Queen Elizabeth II celebrated becoming the worldā€™s longest reigning monarch in September 2015, the Prince of Wales became the longest-waiting heir to the throne in the history of the British monarchy, Bedell Smith said.

Because of his lengthy wait on the sidelines, Bedell Smith said Prince Charles public persona has often been dwarfed by those around him.

ā€œI think that has been the fundamental dilemma of his life,ā€ she explained. ā€œHe was overshadowed by Diana. Heā€™s overshadowed by this much-beloved mother of his and now these sons who have captured the public imagination and are doing very good work.ā€

Bedell Smith described the future king as ā€œsensitiveā€ and ā€œvulnerableā€ as a child. She said he was brought up in ā€œtough wayā€ by his father, Prince Philip, and that he wasnā€™t a dominant ā€œalpha-maleā€ like his father was.

ā€œThere was a quote from Winston Churchill who met him when he was four years old and he said, ā€˜Heā€™s a little boy who thinks too much,ā€™ā€ Bedell Smith recalled.

Prince Charlesā€™ romantic life

Bedell Smith delved into the Prince of Walesā€™ romantic relationships in her research and said she was surprised to discover that he had such a long history with his current wife Camilla Parker Bowles. She said the prince fell in love with the Duchess of Cornwall from almost the first moment he met her in 1972 at a friendā€™s apartment.

Throughout Prince Charlesā€™ highly-publicized and tumultuous marriage to Princess Diana, Bedell Smith said the Duchess of Cornwall had always been the princeā€™s love.

ā€œThey had a romance before he met Diana and then five years after he was married to Diana he resumed with Camilla when he said on television the marriage had irretrievably broken down,ā€ she noted.

Bedell Smith Prince Charles and Princess Dianaā€™s marriage fell apart because the couple hardly knew each other when he proposed, there was a large age difference between them and the princess had some emotional issues that the prince was ill-equipped to handle.

ā€œDiana came along and she looked good on paper. She was from a grand aristocratic family. She was sweet, she was wonderful with children, she was beautiful and he thought he could fall in love with her,ā€ she said.

Despite the negative publicity the Prince of Wales received in the wake of his failed marriage and her death in 1997, Bedell Smith said the portrayal of him being cold and unfeeling is inaccurate.

ā€œHe just has this wonderfully wide range and heā€™s so earnest and he cares so much,ā€ she said.