Jake McDorman stars in "Limitless"

There's an urban legend that claims we only ever use 10 percent of our brains. While this is actually just a myth ("MythBusters" even went to the trouble of debunking it), it hasn't stopped anyone from using the notion as a compelling storytelling device. Most recently, the concept was thrust into public consciousness in 2001, when Irish writer Alan Glynn's techno-thriller novel "The Dark Fields" was published, and the idea rose to the forefront again when "Limitless," the film based on Glynn's novel and starring Bradley Cooper, came out in 2011.

"Limitless" proved popular at the box office, grossing $152 million worldwide against a $27 million budget, and it was only two years later that Cooper announced he would lead a team of executive producers and create a television series based on the movie. The series, aptly titled "Limitless," premiered in September and has also enjoyed moderate success. With only a few episodes left to go until the finale, a new episode of the dramedy airs Tuesday, April 5, on CBS.

Jake McDorman ("Greek") stars as Brian Finch, who, at the start of the season, was a struggling musician and general burnout. Now, after being introduced to the mysterious and revolutionary drug called NZT-48, he's suddenly able to recall every detail of his life every time he takes a pill. Of course, instantly becoming the smartest man in the world turns some heads, and he is ultimately recruited by the FBI.

Jennifer Carpenter ("Dexter") plays Rebecca Harris, the FBI special agent to whom Brian lends his newfound abilities to help solve weekly cases. Rebecca knows quite a bit about NZT-48 and what it can do because her father once visited her while on the drug before turning up dead a few weeks later.

The characters rely on each other quite a bit in the series, and the chemistry between the two actors is, thankfully, very apparent. In an interview with Headlines and Global News, McDorman explained how quickly the duo clicked and what made it such an instantaneous connection:

"We read the script, like, two weeks before we started shooting. It was all very fast, but [the chemistry] was instant from the table read. When I met Jennifer, she reminded me of my sister, who was also eight months pregnant, and I was like, 'You remind me of my sister, but maybe that's just the baby thing?' It's a really cool relationship and I'm glad that it is that relationship."

Yep, you read that right. Carpenter was eight months pregnant when the pilot was filmed, but thanks to a killer wardrobe team and some fancy camera work, audiences at home were none the wiser, and the rest of the cast was able to play it off like it was nothing.

"The rest of the cast" refers to a couple of actors who know their way around the biz. Hill Harper, best known for his role as medical examiner Sheldon Hawkes in "CSI: NY," and Mary Elizabeth Mastrantonio, who was nominated for both a Golden Globe and an Oscar for her turn in "The Color of Money" (1986), round out the main cast as Special Agent Spellman Boyle and Special Agent in Charge Naz Pouran, respectively.

Jennifer Carpenter as seen in "Limitless"

Also making occasional appearances in the TV adaptation is none other than the "Limitless" star himself, Cooper. He reprises his role as Eddie Morra from the film, though now he's Sen. Morra, and he's gunning for a presidential nomination. Cooper serves as executive producer for the series, and evidently handpicked McDorman for the series' lead role:

"I got the script from my agents with kind of a note that was like, 'Hey they'd like to meet with you. Apparently, Bradley thinks you would be great for the lead,'" McDorman said at the Television Critics Association press tour last summer. "I totally didn't believe them at all, and at the end of the meeting they were like, 'Yeah, Bradley really has you in mind for this.'"

Cooper and McDorman have a little history together, aside from existing in the same fictional TV universe. Cooper starred in the 2014 Oscar-winning drama "American Sniper," based on the true exploits of late U.S. Navy SEAL Chris Kyle, who was the most lethal sniper in U.S. military history, having amassed more than 160 confirmed kills. McDorman co-starred as a member of Kyle's unit during the sniper's third tour, Ryan "Biggles" Job.

While the old wives' tale that we only use 10 percent of our brains may be false, that doesn't make the concept any less interesting. The idea spawned a popular book in the early 2000s and a moderately successful movie in the early 2010s, and now it has spawned an equally popular television series. On the backs of two leads who possess great on-screen chemistry and infrequent, yet pertinent, appearances of a familiar face, it's easy to see why "Limitless" is pushing the boundaries.

With only a few episodes to go before the finale, catch a new episode of "Limitless" airing Tuesday, April 5, on CBS.