Kate Middleton was given this sweet nickname by Prince Harry: report

Prince Harry used to call his sister-in-law the Duchess of Cambridge Kate Middleton by her nickname 'Big Sister', according to media reports.

According to the profile on Prince Harry published by the Newsweek in 2017, the Duke of Sussex and Kate Middle were very close to each other even before her marriage with Prince William. They have been together even since he was a teenager.

Kate used to spend considerable time with the royal family and when she was engaged with Prince William, she was given an adorable nickname by her brother-in-law Prince Harry.

Brothers Prince William and Prince Harry have remained closed friends since the demise of their mom Prince Diana. Their affection grew more when Kate Middleton stepped into the royal family.