Helicopters, loud sound effects, perhaps celebrity sightings planned for 'Matrix' set in San Francisco

SAN FRANCISCO (KGO) -- It's not a bird, it's not a plane, but if you look up while in San Francisco's financial district Sunday night, you just might see two low-flying helicopters.

The aircraft will come complete with sound effects and maybe Keanu Reeves?

The Hollywood star has been seen filming "Matrix 4" around the city in the past couple weeks.

RELATED: Fans wait for hours for possible sighting of Keanu Reeves on 'Matrix' set in San Francisco

ABC7 News was on Keanu watch, spotting him on set Saturday night.

An Instagram post by Jon Robson shows Mr. Reeves and his co-star Carrie-Ann Moss rolling by on a stunt bike also in San Francisco Saturday evening.

If you do venture downtown, remember street closures in the area will be in effect.

Alert SF sent a notification on Feb. 16 saying, "Planned Flyover: 2 low-flying helicopters with sound effects will be conducting flyovers in the Financial District on 2/16 from 6PM-12AM for filming in support of movie production. The aircraft will fly at approximately 300-1,500 ft. Street closures in the area will be in effect."

RELATED: Keanu Reeves Watch: Here's where 'The Matrix' star has been spotted in San Francisco Bay Area

Otherwise stay tuned for the latest on the "Matrix 4" film shoot and the local Keanu watch here on ABC7News!