It’s not a slice of pizza — it’s a Secret Service pin.

Donald Trump’s inner circle can be identified by a triangular pin that separates them from other visitors at Trump Tower.

Seen on the lapels of close aides, the gold-rimmed crimson triangle identifies them to the Secret Service and allows them to enter and exit the security perimeter as they please.

Those with pins include incoming White House press secretary Sean Spicer — seen wearing one in the Trump Tower lobby Thursday — and the senior adviser to the president for policy, Stephen Miller.

The pin had been the subject of rampant speculation online, with even “Star Trek” actor George Takei questioning its purpose.

“This symbol’s meaning is tough to pin down,” he tweeted.