The nation's theater chains want you to spend a day at the movies this weekend. More than 3,000 theaters will be participating in the first ever National Cinema Day on Saturday, Sept. 3.

Theaters will be selling tickets for every movie — including more expensive formats like IMAX and 3D — for only $3.

Jackie Brenneman, president of the nonprofit Cinema Foundation, tells CNBC Make It that the idea for a national movie theater holiday was in the works well before 2020, but that the Covid-19 pandemic forced those plans to be postponed.

After Regal Cinemas parent company Cineworld held a similar event in the UK in February to great success, Brenneman said planning began in earnest to replicate the promotion across the pond.

"It gave a model template for how we could do something at that scale in the United States," she says.

In addition to being a "thank you" to fans who returned to movie theaters in droves during the summer blockbuster season — Tom Cruise's "Top Gun: Maverick", for example, has earned the sixth highest domestic gross ever with its $692 million haul — the hope is that people who haven't been to the movies in a few years might be tempted to visit their local theater.

"It's an opportunity [for moviegoers] to see a movie again, or see a movie that they were maybe on the fence about," she says. "For people who haven't come [to the movies in a while], this gives them an opportunity to see how great movie theaters are."

The flat $3 price for any movie in any format is also meant to encourage moviegoers to check out premium formats such as Dolby and IMAX.

"It's an opportunity to get people to try out the new technologies and see how they like it," Brenneman says.

Here's everything you need to know about National Cinema Day.

When is National Cinema Day?

The movie holiday will be held on Saturday, Sept. 3.

Where can I buy the $3 tickets?

You can get your tickets by visiting your local theater's box office, including top chains like AMC and Regal, or by going to online ticket brokers. For a list of participating theaters, visit the National Cinema Day website.

Be aware that the $3 ticket price does not include tax, and is still subject to any third-party ticketing fees that sites may charge.

What movies are eligible for the $3 National Cinema Day promotion?

Every movie currently showing in theaters will be available for $3. Whether you want to go to an 8 p.m. IMAX screening or a matinee showtime, the price will be the same.

Can I buy my $3 tickets in advance?

Not only can you order your seats ahead of time, Brenneman actually recommends it.

"My one piece of advice is to buy your tickets in advance," she says. "If there's a specific movie or a specific technology you're excited about, buy those tickets early."

Will National Cinema Day be an annual event?

There are thus far no plans in place to repeat National Cinema Day next year, but Brenneman says the hope is this won't be a one-off event.

"We'll work really closely with all of our partners to make sure that we evaluate the successes this year and figure out how we can build it even better for everyone next year," she says.

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