After a quarter-century run, the Japanese boy band SMAP has decided to call it quits on Dec. 31, its management agency said in a press release Sunday, shocking die-hard fans in Asia and around the world.

Some of the members of the synchronized five-man idol group — Takuya Kimura, Shingo Katori, Goro Inagaki, Tsuyoshi Kusanagi and Masahiro Nakai — believe it’s best to go their separate ways, and their decision will be respected, Johnny & Associates said in a statement on its website.

“Some members have expressed their wish to disband, rather than to suspend” SMAP’s active schedule as a group, the statement said.

“It was a very difficult decision, but we have judged it will be difficult to continue its activities as a group, although it was not a unanimous choice by the members,” the agency said.

Formed 25 years ago, SMAP is one of the most successful pop groups in Asia. Debuting in the 1990s when they were teens, the five soared to stardom by wowing audiences with upbeat, synchronized song and dance routines, before experimenting with comedy skits on variety TV shows. SMAP’s 2003 single “The Only Flower in the World” sold over 2 million copies.

Although the group will disband, the statement said the members will continue to work with Johnny & Associates as individuals.

Signs of the breakup had been brewing for months.

In January, several media outlets reported SMAP was on the verge of splitting up. Then earlier this month, Johnny & Associates, one of Japan’s most powerful talent agencies, proposed that SMAP go on hiatus “for the time being.”

But that suggestion was apparently rejected, the company said. “We apologize for not being able” to keep SMAP together, it said.

Later, each of the five members issued individual statements to the press.

The popular Kimura, better known as “Kimutaku,” sounded the most emotional about the decision.

“Honestly speaking, the (plan to) dissolve the group couldn’t be more regrettable,” he said. “But under the current situation, we have no choice but to swallow (such a bitter pill) because we couldn’t do anything, either a 25th anniversary concert or other activities, unless all five of us got together,” Kimura wrote.

“This is what has led to the our ‘dissolution,’ which is really shameful. I’m at a loss for words right now.”

Nakai, SMAP’s leader, also expressed remorse. “For all of our fans and related parties, we now report that SMAP will disband,” Nakai wrote. “We have caused you troubles, worried you, and we owe you much. We are really sorry for creating this situation. We apologize.”

Kusanagi sounded unaffected by the development. “We have chosen to disband SMAP,” he wrote. “We will continue to work hard. We will be happy if you keep watching us with your warm thoughts,” he said.

Fans were shocked and disappointed as the news sunk in.

“I want to see the five of them together again,” pleaded a 17-year-old girl from Ibaraki Prefecture who said she was under the belief that the band members had patched up their differences since January.

Another fan expressed dismay while waiting in line with hundreds of others at Johnny’s Harajuku store in Shibuya, which sells merchandise related to its celebrity clients.

“I’ve prayed for the group’s unity since January when the possible split-up was reported,” said the 22-year-old woman from Hiroshima. “I was thinking, ‘It can’t be true, it can’t be true.’ Now it’s really happening . . .”

The news attracted heavy media attention overseas as well, especially in China, Taiwan and South Korea, where fans were equally shocked.

An entertainment news site in China said it was stricken with grief that the popular idol group, which played a rare concert in Beijing in September 2011, has called it quits.

“The one and only flower in the world has withered,” a Chinese fan wrote on the internet, playing on the group’s smash hit “The Only Flower in the World.” Another said, “The springtime of my life is gone.”

The entertainment website posted the full text of the Japanese statement released by Johnny & Associates, as well as the five members’ comments translated into Chinese.

Backed by the leadership of the Communist Party of China at the time, the September 2011 concert in Beijing helped ease rising tensions between Japanese and Chinese after a high-profile incident in September 2010 in which a Chinese trawler collided with two Japan Coast Guard ships near the Japan-administered Senkaku Islands, which China and Taiwan claim.

Online, a fan posting praised SMAP as a top pro-Chinese idol group and noted that its members have met with then-Premier Wen Jiabao.

Taiwan’s Central News Agency and South Korea’s Yonhap News Agency also reported SMAP’s decision soon after the Johnny’s announcement.

Information from Kyodo and Jiji added