Invitation to the Wedding on AllMovie

Good performances (by Ralph Richardson as a befuddled pastor and Paul Nicholas as David, an unwitting bridegroom) help along this otherwise weak comedy-romance about David, an American who stands in for the groom at a wedding rehearsal -- only to later discover that the wedding was accidentally real. His "bride" is Lady Anne (Susan Brooks). After the "rehearsal," the unintended couple spend an idyllic week going on picnics, riding horses, and generally enjoying the countryside and each other's company. By the end of the week, Lady Anne has changed her mind about her actual, pending marriage -- and though it does not seem to be an issue, her pending marriage would only make her a bigamist after all.