Claire Louise van Kampen, Lady Rylance (3 November 1953 – 18 January 2025) was an English director, composer, and playwright.

Van Kampen composed music for productions in both London's West End theatres and on New York City's Broadway that often starred her husband, covering a wide range of repertoire from Helen by Euripides to contemporary plays such as Nice Fish; she also worked as musical director and stage director for some of them.

[6] At the National, she met her future husband, Mark Rylance, and she composed the music for his 1989 performance as Hamlet at the RSC.

[10] She worked at the Globe during Rylance's term as the theatre's first artistic director[3] and remained there as musical consultant and resident composer under his successor, Dominic Dromgoole from 2007 to 2015.

[6] In the spring of 2007, she received the Vero Nihil Verius Award for Distinguished Achievement in the Arts, conferred upon her by Concordia University in Oregon, United States.

Together with Rylance and theatrical designer Jenny Tiramani, she received the 2007 Sam Wanamaker Award for her founding work during the opening ten years at Shakespeare's Globe Theatre.

[4] She wrote a historical play, Farinelli and the King, about the relationship between the castrato Farinelli and the Spanish King Philip V.[4] It was first performed at Sam Wanamaker Playhouse in February 2015, then at the Duke of York's Theatre in the West End of London from September to December 2015, with Rylance as Philippe V.[4] It was also produced on Broadway, directed by John Dove at the Belasco Theatre.