be a revelation

be a revelation

To be different than one anticipated, often in a good way. Dana's performance in the play was a revelation—I had no idea she was such a talented actress.
See also: revelation
Farlex Dictionary of Idioms.

come as/be a reveˈlation (to somebody)

be a completely new or surprising experience; be different from what was expected: His performance in the race today was a revelation to everyone. My trip to Texas was a revelation.
See also: come, revelation
Farlex Partner Idioms Dictionary
See also:
  • come as/be a revelation
  • revelation
  • come as a revelation
  • pop into (someone's) head
  • a man for all seasons
  • season
  • astound
  • astound (one) with (something)
  • astound with
  • have a light bulb go on in (one's) brain