Katharine Payne Towne (born July 17, 1978) is an American actress, born in Hollywood, California to Julie Payne, an actress, and Robert Towne, an Oscar-winning screenwriter, director, and actor. She is a grandchild of actors John Payne and Anne Shirley.
Towne's career began with a small role in the 1998 movie Girl. She then appeared in Go, She's All That, But I'm a Cheerleader and The Bachelor, as well as guest-starring as Sunday on Buffy the Vampire Slayer.
In 2000, Towne starred as Riley on NBC's short-lived sitcom M.Y.O.B.. Since then she has appeared in a number of feature films, including The In Crowd, What Lies Beneath, Town & Country, Mulholland Drive, Evolution, Something New and Blades of Glory. She also played a character called Erin in Sweet Home Alabama; her scenes didn't make the final cut, but were included on the film's DVD release. Towne played Mason on HBO's Tell Me You Love Me. Towne was married to English actor Charlie Hunnam from 1999 to 2002.