The filmmaker helmed the hit 1998 classic starring Hugh Grant and Julia Roberts and was also known for directing My Cousin Rachel starring Rachel Weisz.
A statement from his publicist to the PA news agency said: “It is with great sadness that the family of Roger Michell, director, writer and father of Harry, Rosie, Maggie and Sparrow, announce his death at the age of 65 on September 22.”
The son of a British diplomat, Roger was born in South Africa and lived in Beirut, Damascus and Prague as a child.
His films include Enduring Love, Morning Glory, Persuasion, Blackbird and the forthcoming The Duke starring Dame Helen Mirren, Jim Broadbent and Matthew Goode.
His theatre credits include Nina Raine’s Consent, Harold Pinter’s The Homecoming and Dylan Thomas’ Under Milk Wood, with many of his productions playing at the National Theatre.
Roger was married to Line Of Duty and Motherland star Anna Maxwell Martin from 2002 until their separation last year.
The couple had two daughters together, with Roger also father to two children from his first marriage to actress Kate Buffery.
This article originally appeared on HuffPost UK and has been updated.