show one's colours BrE
show one's colors AmE

You don't want to be around when he shows his true colors.

"Is this what war does to people, or do they just show their true colors?"

But the past few weeks he had shown his true colors.

Still, there are times when they feel forced to show their colors.

But it was under game conditions where the Voodoo5 5500 showed its true colors.

"You can't expect such a child to show his or her true colors for the first 30 days," he said.

Their screens are small, and some do not show color, in part to save power.

He nodded, his face showing color again, and walked to the door.

He could hang it all out, show his true colors.

Did she not show her true colors last night outside of the theatre?