Belinda Anthea Stewart-Wilson is a British actress who played Polly McKenzie in The Inbetweeners. Stewart-Wilson was born on 16 April 1971 in Kensington, the youngest of three daughters of Lieutenant-Colonel Sir Blair Stewart-Wilson, a British Army officer, and his wife, Helen Mary Fox.

Stewart-Wilson grew up on military postings in the UK, Germany, and Austria before her family settled in London, her father becoming an Equerry to Queen Elizabeth II. She was educated at St Mary's School, Calne in Calne, Wiltshire and Hurst Lodge School in Berkshire, before completing a three-year degree in classical acting at the Webber Douglas Academy of Dramatic Art, in London. Stewart-Wilson's first television role was in the series Shine on Harvey Moon, a show based in post-war London.