Police are warning drivers on River Road that a movie production that caused big delays Thursday may do the same thing Friday during morning rush hour.
Production trucks and trailers are in the area of the Saints Peter and Paul Antiochian Orthodox Christian Church, which is on River Road just south of Norton Road.
The crews are in town to film a BBC movie starring famous British actress Judi Dench.
Thursday morning's traffic backup reportedly started near Norton and went northwest for miles on River Road back to its intersection with Travilah Road.
Drivers are being warned they may want to avoid that area Friday morning.
Montgomery County police say the crew wasn't allowed to film during rush hour. But apparently the sight of all the production equipment along with a lot of police cars led to rubbernecking.
Also, some of the production equipment was reportedly moved across the road at times.
"The traffic was terrible, I couldn't get to work," said Potomac resident Cindy Miller. "It went forever. It was ridiculous, couldn't figure out what it was all about."
Some drivers were angry that a movie would cause so much traffic hardship.
But Miller says when she found out what had caused the backup, she no longer minded having had to sit through it.
"I can't wait to see it," she said of the movie being filmed.
The movie is called "Philomena Lee." Dench plays an Irish woman who searches 50 years for an illegitimate son taken from her shortly after she gives birth. The search takes her to the United States.
In addition to River Road in Potomac, the movie has also been filming in another Montgomery County town -- Poolesville.
Dench is making quite a bit of international news this week, but it's not related to "Philomena Lee."
For the seventh time, Dench plays the iconic character M in the new James Bond movie "Skyfall," which has already opened overseas and opens in the United States Friday.