behind the scenes

Short definition from Wiktionary

Prepositional phrase

1. 1
   behind the scenery and stage area; backstage; among the actors; during the production or rehearsal
2. 2
   In secret; out of public view.

Adjective

1. 1
   Being or working out in secret or out of public view.
2. 2
   Divulging or reporting hidden workings.
3. 3
   Alternative spelling of behind the scenes.