LOS ANGELES — Chris O’Donnell, wearing a navy blue vest and jeans, stood in the sun near La Brea Tar Pits, where a crowd of curious museum visitors and tourists were snapping photos of the star of the CBS hit series “NCIS: Los Angeles.”

As actor and rapper LL Cool J (aka James Todd Smith) rested in a director’s chair and signed autographs for children, O’Donnell waited for his cue to chase down his target standing a few yards away: a hapless T-shirt vendor dressed in a saber-toothed tiger costume who has information about a Mexican cartel.

“I’ve never been to the La Brea Tar Pits,” said O’Donnell, a Chicago native who was barely breaking a sweat after doing multiple takes of the chase scene last Friday afternoon. “You get to see so much of L.A.,” he said of the show’s local filming.

The action series, about a criminal investigation branch of the U.S. Navy, features not only LL Cool J and O’Donnell as special agents, but another, often overlooked character: the city of Los Angeles. Showcasing such landmarks as the Griffith Observatory, Union Station and La Brea Tar Pits, “NCIS: Los Angeles” is something of an anomaly in Hollywood in that it shoots mostly on location in greater L.A., which often stands in for other cities, rather than on a soundstage.

“We spend a lot of time re-creating other cities and places around the world, and it’s very rare that we get the opportunity to shoot Los Angeles for Los Angeles,” said Shane Brennan, the creator and writer for the series, which premieres its second season Sept. 21.

Brennan, a native of Australia, said he set the series in Los Angeles in part to make it as different as possible from the original series, “NCIS,” which shoots in Santa Clarita and is set in Washington, but also to tap into the area’s diverse locations.

“I had always thought it had been a long time since a show showcased Los Angeles, maybe not since ‘L.A. Law’ in the 1990s and ‘Dragnet,'” he said, referring to the famous TV crime drama from the 1950s and 1960s.

“You think you know what L.A. looks like because of what you’ve seen on movies and postcards, but here’s another side of it,” Brennan added.

Last season, producers convinced transportation officials to let them shut down the 101 Freeway on a Sunday to film a car chase that spilled onto Mulholland Drive and culminated in a gun battle in front of the Griffith Observatory.

“We try to pack as many iconic locations as we can into the story,” said John Peter Kousakis, executive producer on the show, which is based at the Paramount Studios lot in Hollywood. “For me, being a native Los Angeleno, it’s like Nirvana.”

Unlike most TV shows, which do the majority of their filming on soundstages, “NCIS: Los Angeles” films five to six days out of eight on location. Filming so heavily on location, which is more expensive than on a studio lot, isn’t cheap. It costs nearly $3 million an episode to film the show, which employs a crew of about 150.

But the exterior shots are crucial to the story. “Our show looks best when we’re outside,” said location manager Tony Salome. “It’s all about the action.”

That’s all right with LL Cool J. “For me, running, jumping, playing a Navy SEAL and getting to play with a lot of big toys — it’s fun,” he said. “I’m having a good time.”

Only subscribers are eligible to post comments. Please subscribe or to participate in the conversation. Here’s why.

Use the form below to reset your password. When you've submitted your account email, we will send an email with a reset code.