This was all done for the express purpose of having the
Supergirl in the comic books be consistent in appearance to
the Supergirl in the
forthcoming movie.
A version of this costume was made for the film and was worn by
actress Helen Slater
in some test footage shot prior to the actual production of Supergirl.
Ultimately, however, the outfit never actually made it to the big
screen.
The movie costume underwent extensive redesign before shooting
began and the version
used in the film did not have the headband or the ornate
collar design.