"They have a sisterly bond and Sophie is like the older sister Kate never had," royal author and commentator Ingrid Seward told Hello! of the royal duo. Sophie, the Duchess of Edinburgh, married Prince Edward in 1999 and shares two children, Lady Louise and James, the Earl of Wessex, with the Duke of Edinburgh.

Kate Middleton and Prince Edward's wife, Sophie Wessex, have developed a strong friendship over the years — so much so, their bond was on full display during Remembrance Sunday on November 10. According to royal biographer Ingrid Seward,

It was evident in their joint appearance at Remembrance Sunday that Kate Middleton and Sophie, Duchess of Edinburgh share a bond.

Sophie's ability to balance royal duties with personal challenges has made her one of the most respected members of the Firm - but it’s her quiet mentorship of the Princess of Wales that stands out

Catherine, Princess of Wales has always been a big sister figure. She was one year old when her little sister, Pippa Middleton, came along, and five when her baby brother, James Middleton, was born. Their relationship with one another only seems to have strengthened as they've entered the public eye,

Princess Kate and the Duchess of Edinburgh were given "more knowledge" before making a key move, a royal commentator has claimed. Kate, 42, and Sophie, 59, both married into the Royal Family from middle-class backgrounds and have young children,