a police uniform, or a musical instrument. On other occasions, where a costume has already been prepared (for example, to fit another actor who is now unavailable), a background actor may be selected as a "costume double" simply because they are the right size to fit it. On smaller productions or student films, background actors may be hired en masse with little formality. The length of a background actor's employment on a production largely depends on the needs of the director and the scenes being filmed. Some background actors are needed on the set only for a day or two and are paid on a daily basis, while others may remain with the film for an extended period. For instance, on James Cameron's film Titanic, a group of 150 "core background actors" was hired to play the ship's passengers, and employed throughout the filming. Salary and working conditions United Kingdom In the United Kingdom, the distinction between an actor and an extra is defined by agreements between the actors trade unions Broadcasting Entertainment Cinematograph and Theatre Union (BECTU) and Equity, and the various commercial trade and production bodies. These state that once a performer says 13 or more words in any scene, they must become a contracted actor in that production. Minimum pay rates are defined by UK Government minimum wage regulations, and both BECTU and Equity have agreed rates with each body. However, even on non-union productions an extra's pay is an agreed day-rate for ten hours of production time. All performers under agreement with BECTU/Equity are paid on-going royalties. Hence on many advertisements, which are often shown multiple times and distributed internationally, whilst the extra is paid a contracted day-rate, the largest payment is nominally due from ongoing royalties. Due to the resultant complex calculations from multiple international showings, performers under a union managed agreement are often bought-out of their advertisement royalties with a one-off payment. United States Since 2012, in the US, most major film and television productions fall under the jurisdiction of the SAG-AFTRA union, previously before SAG-AFTRA was AFL–CIO's affiliate, the two unions were separately named as: Screen Actors Guild (SAG) and American Federation of Television and Radio Artists (AFTRA). SAG-AFTRA signatory AMPTP producers are allowed to hire non-union background actors after a certain number of SAG performers have been cast; non-union background actors are usually paid the minimum wage. On productions outside of union