Born in New York and raised in London, Sian's passion for ballet began during her formative years. Her journey in dance education flourished as she honed her skills at the Beverley School of Performing Arts, the Arts Educational Schools, and ultimately The Royal Ballet School. Sian's illustrious career with The Royal Ballet commenced in 1996, leading to her well-deserved promotion to First Artist. In 2016, she gracefully transitioned from her role as a professional dancer to assume the esteemed position of Assistant Ballet Mistress of The Royal Ballet. Recognising her exceptional talents and dedication to the art form, Sian was later elevated to the role of Repetiteur in 2021, solidifying her status as an esteemed figure in the ballet world.

Repertory included Zulme, Bathilde and pas de six (Giselle), Courtesan (Manon), Fairy of Generosity, Gold Fairy, Fairy of the Woodland Glade and Diamond Variation (Sleeping Beauty), Eldest Sister (Las hermanas) and roles in Romeo and Juliet, Cinderella, Patineurs, Fille mal gardée, Anastasia, Serenade, Concerto, Symphony in C, Scènes de ballet, All Nighter, Room of Cooks, When We Stop Talking, Cheating, Lying, Stealing, Sinfonietta and Don Quixote. She created roles in Sawdust and Tinsel, There Where She Loves and The Winter’s Tale.