Geraldine Margaret Agnew-Somerville (born 19 May 1967) is a British actress.
She is perhaps best known for her roles in the film Gosford Park (2001) and the Harry Potter film series (2001–2011).
Her other notable roles were in My Week with Marilyn (2011) and Grace of Monaco (2014).
In 1995, Somerville was nominated for a BAFTA Award for playing Jane Penhaligon in the television series Cracker from 1993 to 1995.