Williams and Branagh are on dazzling form as Marilyn Monroe and Laurence Olivier, while a raft of spangled British thespians (Judi Dench, Derek Jacobi, Dominic Cooper, Julia Ormond) offer lively support in the director Simon Curtis's adaptation of a memoir about one young man's brief encounter with the tragic blonde supernova. Williams's performance is already earning end-of-year critics' awards in the US and she's shaping up to be serious competition at next year's Oscar ceremony for Meryl Streep, still the front-runner for her much-lauded turn as Margaret Thatcher in The Iron Lady. The story takes place over one week in the summer of 1956, when Monroe arrives in England to shoot The Prince and the Showgirl with co-star/director Olivier and finds an ally on the difficult set in callow errand boy Colin Clark (Eddie Redmayne). Based on Clark's recollections, the story's sympathies naturally lie with Marilyn but Curtis keeps the balance right, portraying the extreme exasperation of trying to work with the chronically tardy, emotionally needy bombshell - especially for a diehard old luvvie like Olivier. Branagh leans towards impersonation as Olivier but his performance is still laced with wit, intelligence and bite. The film misses him badly when he's not on screen, which is most of the second half when Monroe's relationship with Redmayne takes a turn towards the romantic. As for Williams, she is poignant and captivating, bringing Monroe's messy vulnerability to vivid life. Along with some exquisite set and costume design, anyone enamoured of Hollywood history will be smitten by this nostalgic and amusing culture-clash romp.