BEA is an acronym for the British Equity Actors' Association, which is a trade union representing professional performers in the United Kingdom. Arthur and Lillie are two of the most famous members of the BEA, having both been involved in the entertainment industry for many years. Arthur was a well-known actor and singer, while Lillie was a renowned dancer and choreographer. Both Arthur and Lillie have made significant contributions to the British entertainment industry, and their work is still celebrated today.