[under wraps] {adv.}
or {adj. phr.}
Not allowed to be seen until the right time; not allowed to act or speak freely; in secrecy; hidden. — Usually used with "keep".
* /We have a new player, hut we are keeping him under wraps until the game./* /What the President is planning will be kept under wraps until tomorrow./* /The spy was kept under wraps and not allowed to talk to newspapermen./
Compare: UNDER COVER.