The stampede to see South Korea’s most reluctant celebrities starts early, often before they’re out of bed.

On many weekends, hundreds of tourists appear at the tumbledown homestead to meet 82-year-old farmer Choi Won-kyun and his loving but nagging wife, Lee Sam-sun.

They’re the unlikely stars of “Old Partner,” a documentary that chronicles two years in the lives of the hard-working couple as they await the death of the aging cow that has served them faithfully for 40 years.

The movie shattered box-office records here for an independent film, becoming an instant low-budget classic, a fable about love, loyalty and rural Korean values -- and also a touching, sometimes funny, tale of a wife’s jealousy over the bond between husband and bovine.

But since the movie’s January premiere, a near-daily invasion of curious visitors has threatened the tranquil life of the illiterate couple, who just want to be left alone. Everyone wants a piece of them, pestering for countless photos: Stand here. Pose there. Bale more hay. Smile! Now take us to the old cow’s grave site for just a few more snapshots. The boldest intruders barge into the house uninvited.

“I’m gratified that people are interested in my parents,” says Choi Won-kyun, the eldest of the couple’s nine children. “If only they would have a sip of coffee and leave, but they stay. What can my parents do? Hospitality is part of rural life. We don’t have any choice but to welcome them.”

The project brought first-time director Lee Chung-ryul overnight success as well as a hard lesson in filmmaking: Sometimes a documentary can imperil the very subjects it works to portray.

“From the start, I promised I would protect this couple,” he says. “But this movie has become more successful than I ever imagined. It has taken on a life of its own.”

Lee wanted to make a documentary about the beauty of simple things. To tell the story, he chose a farmer who preferred his devoted old cow over any modern tractor.

He was inspired by his own rural childhood and the novelist Pearl S. Buck, who nearly a century ago wrote of a farmer and cow she saw on a trip to Korea.

“She said it was the most beautiful scene she had ever witnessed,” says Lee, 42, a small man with a Beatles-style mop of hair. “Now the cow’s status has changed. They’re no longer family members but seen as pieces of meat.”

For five years, he searched for the right relationship between man and beast. In 2002, he was introduced to Choi, who recently had been informed that his female ox’s days were numbered. She had already lived far longer than most.

The pair’s similarities astounded him: Nearly deaf with a malformed leg, the limping farmer was often forced to crawl across his rice fields. The staggering brown cow, which is never given a name, was no better off. Choi often groomed the skinny animal’s diseased hide and fed her special gruel to keep her strength up.

For Lee, the pair seemed to have a secret pact: Keep working together or we’ll both die.

In 2005, he began shooting what he saw as an intimate chronicle of the cow’s final year. Problems arose from day one.

Choi resisted any intrusion he felt would interrupt his chores. Every time Lee approached with his camera, Choi and his wife stopped talking, or stared as though posing for a snapshot.

So the director affixed microphones to the couple’s clothes and filmed from a distance with a zoom lens.

What his camera captured was a poignant real-life drama, as the woman constantly berated her husband for not exchanging his old partner for a tractor.

In her gravelly voice, she nags him to use chemicals that would improve crop yields and about the energy he wastes doting on the cow -- but especially about her tiring labors caring for both animal and husband.

“We work so hard,” she tells the cow one day. “We both met the wrong man.”

Choi finally relents and takes the cow to sell at market, but he sagely asks for so much money that the cattle buyers laugh in his face.

“This cow is better than a human,” he says. “When it dies, I’ll be its chief mourner -- and I’ll follow. I’m alive because of this cow.”

Later, Choi sits forlornly with his head in his arms as his wife gripes that he loves the cow more than he loves her. He doesn’t react, but when the animal lows, his head jerks up.

“It was a romantic triangle,” says director Lee. “The old woman was jealous because her husband gave the cow more attention.”

The farmer endured both wife and filmmaker.

“There were two things that got him upset,” Lee says. “When his wife started nagging and when he saw me coming.”

A year into the project, Lee found that the old cow was ignoring her stage cue: She refused to die. Making the film with borrowed money, he fought with his producer over the financing and deadline.

“At one point, I told the cow, ‘Could you please die faster?’ I feel bad about that now,” Lee says.

As the animal grows weaker, the couple and cow seem to know the end is near. In one sequence, Lee shows a tear in the eye of the farmer, then his wife, then the cow.

In one of their last days together, the animal struggles during a trip to collect firewood, prompting the farmer to stop the cart. He unloads some of the wood, straps it to his back and walks alongside his old partner in a gesture that signals he considers the two equals.

But Lee, who had parted ways with his producer and was dealing with a budget of less than $1 million, couldn’t be there for every poignant moment. He wasn’t there when the cow finally fell over, unable to rise.

Alerted by the farmer’s eldest son, he made the three-hour journey from Seoul to find Choi weeping as he implored the cow to get up, asking a veterinarian, “What can I do to prolong its life?”

When the animal finally dies, even the wife is moved. “May you go to heaven,” she says. “But why are you leaving before us?”

Finally, Lee had his ending. He went into postproduction, creating movie posters that showed the farmer’s weathered hands holding his keepsake cowbell. In Korean, the film is called “The Sound of the Cow’s Bell.”

Success was immediate. The movie won an award at the prestigious Busan International Film Festival and played at the Sundance Film Festival, prompting Lee to look for a U.S. distributor. (The movie is now showing in Los Angeles at the Mpark4 theater on Wilshire Boulevard.)

South Korea’s previous box-office record for an independent documentary was 120,000 tickets, Lee says. His film has surpassed 3 million. Even President Lee Myung-bak wanted to meet the director.

“One morning I woke up famous,” Lee recalls.

But with fame came a nagging question: How much is an old couple’s privacy worth?

Since the film’s release, Choi’s health has worsened. His younger cow gives him fits, making it impossible to rest. Then there are the crowds.

Choi’s son says the family doesn’t blame Lee.

The director recently made a nationwide appeal to South Koreans to respect the couple’s privacy. But the hordes keep coming.

He holds himself accountable: “I put so much stress on the cow and the old man, their health worsened because of me.”

Lee Sam-sun, her tiny frame stooped low, only three teeth gracing her lower jaw, summons her husband for a picture with several visitors. He shuffles over slowly with his cane but soon disappears back to his farm work.

“My husband makes me so upset sometimes,” the 79-year-old woman announces.

In February, the director staged four sold-out showings of the film at a local community center. Lee Sam-sun, who has lived on the same farm since she married Choi at 16, cried during one scene -- when she watched herself singing a song called “Bring Back My Youth.”

Choi wasn’t interested in seeing the documentary. Even when shown a DVD version on his grandson’s laptop, his eyes soon wandered toward the nearby TV screen.

“That movie was his life,” says the son, Choi. “It was nothing new.”

In this farming town of 35,000, residents are divided over the movie. Some say it makes rural life look too glamorous.

Others fault the family for allowing the old couple to continue working so hard.

“How could nine children let their parents live in such squalor?” asked a convenience store clerk.

And people are starting to gossip: The couple were paid millions for the film, according to one rumor. The children are squabbling bitterly over the spoils, goes another.

Even though he says the family has yet to see any portion of the film’s profits, son Choi says residents approach him on the street or call his home anonymously with the same prying question: How much were you paid?

“One group heard I made a lot of money,” says Choi, 56, a high school art teacher. “They insisted that I donate to their charity.”

His parents once would ask visitors to sign a guest book and then offer a tour of their home and farm. Now their impatience shows.

One day, the old man suddenly asks his wife within earshot of guests: “When are they leaving?” When a visitor asks him about the cow, his wife snaps, “Don’t ask about the dead cow.”

Still, the local tourism board is planning an “Old Partner” museum and has erected signs leading to the farm.

It has collected the elder Choi’s clothes and cane used in the movie. The board even claimed the tarnished cowbell, with plans to sell replicas to tourists.

The family knows the movie could be a ticket to prosperity for their ailing community. They feel an obligation.

Still, as she watches her husband pile wood, Lee admits the stress of celebrity can be overwhelming. “My husband says he gets sick of all this,” she says. “I told him to behave himself.”

She pauses. “I guess I do nag a lot.”

john.glionna@latimes.com