The Prime Minister's remarks put in the public arena a debate which has been going on behind the scenes for months. 2 undertaken or done so as to escape being observed or known by others.
behind-the-scenes negotiations that resulted in the hostages being released unharmed.

Antonyms for behind-the-scenes. in private or in secret, rather than publicly. held or kept privately by or among a few key or influential persons: behind-the-scenes negotiations.
Definition of behind-the-scenes.

The debate was postponed for a third time after another day of intensive behind-the-scenes negotiations. 2 : revealing or reporting the hidden workings a behind-the-scenes account a behind-the-scenes … This term alludes to the various activities that go on behind the curtain in theaters, out of the audience's view. In secret or private, away from public view, as in His struggle for the top position took place strictly behind the scenes. occurring backstage: the behind-the-scenes … behind the scenes. common, open, public.

[Late 1700s] Also see behind closed doors.

Easy Learning Idioms Dictionary. adjective.

behind the scenes.

happening or conducted out of view of the general public: The behind-the-scenes preparations made the convention a huge success. 1 : being or working out of public view or in secret behind-the-scenes lobbying for more money a behind-the-scenes player.