The married couple is preparing to film two videos for their popular YouTube channel, Fitness Blender. Kelli, who is 5’8” with long dark blonde hair, and the owner of the most dramatic waist-to-booty ratio this side of Kim Kardashian, writes her routine on a whiteboard.

A cameraman captures different angles with two cameras as Kelli works through a punishing round of squats and weight exercises. She says to her unseen viewers, “This next interval is a little mean.” Daniel, 35, who watches from a nearby couch, smiles.

A part of the Powerblock Adjustable Dumbbell set falls out and drops to the floor. Undeterred, she continues. In Hollywood, someone would have yelled, “cut!” but this is part of Fitness Blender’s charm, and why they have so many YouTube Fans.

Kelli and Daniel Segars are two of YouTube’s biggest stars, with 330 million views on their workout videos since they started in 2010. They now run the multimillion-dollar website FitnessBlender.com.

“We don’t promote perfection,” Kelli, 31, says. “We’re not flawless. We hear so often, ‘Oh my God, you’re real people.’ ”

It’s one reason why they have more than 2.5 million subscribers on YouTube, more than double the number from the beginning of the year, placing them in the Top 500 of most subscribed channels, out of hundreds of millions.

All told, their videos — more than 450 now — have accumulated a combined 330 million views since they uploaded their first clip in 2010. Their most popular, “10 Minute Abs Workout,” a simple, short and torturous routine, has 23 million views. (It helps that workout videos by nature encourage repeat viewing.)

They’ve made numerous best-of lists: including BuzzFeed, Forbes and People magazine. In the Internet’s alternate universe, they are bigger than other more well-known competitors in the exercise space: by comparison, the channel Be Fit, home to celebrity trainers like Jillian Michaels and Denise Austin, has 1.9 million subscribers.

“If you look at their YouTube channel compared to ours, we trounce them severely,” Daniel says proudly. “If you want to look at just that one metric.”

The success of their videos has allowed them to work full time on the company since 2012 which includes their website, FitnessBlender.com, which they are relaunching in early 2016, with an amped-up eating plan. Perhaps a book or a clothing line is in the cards. At this point, anything is possible.

In a way, they have the Great Recession to thank for Fitness Blender’s success. One weekend in August 2008, they got married and closed on their first house, and then, on Monday, Daniel lost the majority of his personal-training clients and Kelli’s hours at the gym selling memberships were drastically reduced.

“In three days it was like everything just got turned upside down,” Kelli says.

When they started Fitness Blender, the Segars hoped it would bring some extra income. At the time, the couple were working numerous odd jobs to stay afloat. Kelli wrote “how-to” articles on the Internet at night while ironically working with an organization that helped unemployed people get back on their feet. Daniel apprenticed as a plumber.

The house they bought at the height of the market fortuitously had a nearly finished garage. They added drywall and painted it white. Devoid of gimmicks, their videos are filmed on a white background and have no music, a decision born out of practicality, not a monastic commitment to minimalism: They used a white background because it was simple and clean; and without music, the videos would never seem too dated, and viewers could choose their own songs.

They spent a few hundred dollars on a camera and used shop lights. They edited the videos themselves using iMovie.

“Oh my gosh, it was so amateur for so, so long,” Daniel says.

Their initial videos were short — 30-second, almost robotic instructions on how do a situp, a toe-crunch or a push-up, but they soon learned that wasn’t what people wanted.

“People like personal. They like to know who they are working out with. So when we made that switch, that’s when we really took off,” Kelli says over lunch at a pub near their house.

Daniel is having a rare “cheat meal”— a burger and fries; she eats a salmon salad. They are still in their workout clothes; she’s wearing a gray sweatshirt adorned with the YouTube logo. Despite six-plus years of being together, they still have the sweet rapport of honeymooners in love. Though many of their videos feature them exercising solo, clips with the two of are charming as well as helpful (one person will demonstrate the harder version of an exercise).

While other fitness videos favor expensive, garish sets, loud, pumping music and celebrity instructors who are toned-and-tanned and blonde and caffeinated and never seem to struggle, the Segars don’t yell relentlessly upbeat motivational mantras. Indeed, Kelli is so shy that in initial videos she didn’t speak on camera at all: Instead, Daniel narrated while she demonstrated the exercises.

“We bring a type of personality to the fitness industry that is very uncommon, because we’re not those … the cheerleader types, boundless energy,” says Daniel. “I mean, I get tired. I don’t necessarily want to work out, but I know I should and I feel better when I do, so that’s why I do. It’s not because I’m like, ‘I got to work out, got to get my max today!’ ”