Spoiler alert: Reading this may or may not (we don’t really know) spoil a surprise in a pilot for a new CBS action series called “Washington Field.”

But Washington-area residents probably should read this so they don’t get alarmed at the 20- to 30-foot fireball from a simulated explosion on Wednesday near a bridge that connects Georgetown to Virginia.

The Metropolitan Washington Council of Governments issued an advisory saying there will be a fake explosion on Wednesday between 9:30 a.m. and noon near Key Bridge that will produce a fireball that will last for about two minutes.

The explosion on the Potomac River will be for a scene in which one of six sculling boats blows up in the pilot for a television series about the Washington field office of the FBI.

The Homeland Security Department, Washington police and fire departments, and the Washington Airports Authority have been alerted.

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Photo credit: Reuters/Hyungwon Kang (Potomac River and Georgetown University during fall)