Philippa Charlotte "Pippa" Middleton (born 6 September 1983) is an English party planner, socialite and younger sister of Catherine, Duchess of Cambridge. Philippa Charlotte "Pippa" Middleton (born 6 September 1983) is an English party planner, socialite and younger sister of Catherine, Duchess of Cambridge. On 29 April 2011, she was the maid of honour at her sister's wedding to Prince William, Duke of Cambridge, second in the line of succession to Elizabeth II's sixteen thrones.