Looking as if they were about to attend a funeral rather than proclaim a resurrection, the five members of one of Japan’s most successful bands of all time have announced that, contrary to media speculation, they aren’t splitting up after all.

On Tuesday night, Smap used the opening of their TV variety show to reassure fans they were staying together, days after reports that they were about to break up sent shockwaves through the country’s entertainment industry and dismayed their millions of followers.

Dressed in black suits and dark ties, the performers bowed deeply before apologising for the “anxiety” they had caused.

They conceded that the group was in the middle of a crisis – perhaps not surprising for a boyband whose members are aged between 38 and 43 – before promising that they would sing together again.

Takuya Kimura, the best-known member, admitted that Smap had been “on the verge of a midair breakup”. But he added: “From now on we will only look ahead and strive to go forward.”

Fans of Smap – an acronym for sports, music, assemble, people – had voiced their disbelief when a tabloid newspaper said last week the band members were about to go their separate ways.

The Nikkan Sports said a disagreement between their manager and senior executives at Smap’s talent agency, Johnny and Associates, would see all of the members except Kimura leave, effectively spelling the end of the group.

As news broke last Wednesday, fans urged each other to buy the band’s old hit songs in the hope that it would prevent the split. By Friday, their 2003 megahit Sekai ni Hitotsu Dake no Hana had reached No 9 in Japan’s Oricon charts.

The news that Smap would stay together generated so much online comment that Japan’s Twitter network briefly crashed, while Tuesday’s front-page headline in the Mainichi Shimbun, a broadsheet paper, said simply: “Smap to go on.”

The group’s swift return to the Japanese pop music firmament even drew a response from the prime minister, Shinzo Abe.

“Similar to the world of politics, there must be many challenges for one group to last so long,” Abe said in response to a question by an opposition MP at a budget committee meeting. “It is good that they will stay together, as that is what their fans wished for.”

The chief cabinet secretary, Yoshihide Suga, applauded the decision, saying it would fulfil the “hopes and dreams of the public”.

While Smap’s unadventurous music and forgettable lyrics have proved a perfect fit for the J-pop template, they are practically unknown outside Asia, where they have built a huge following since releasing their debut single, Can’t Stop!! Loving, in 1991.

Kimura, along with Masahiro Nakai, Goro Inagaki, Tsuyoshi Kusanagi and Shingo Katori, have gone on to appear in numerous TV adverts, dramas and films, and together are worth an estimated ¥20bn (about £120m).

Smap’s on-off breakup generated rare public discussion of the group’s powerful management agency, whose octogenarian head, Johnny Kitagawa, has found himself at the centre of controversy, despite his attempts to shun the media limelight.

Formed in 1988, when the members were teenage backing dancers, Smap conquered the domestic market before going on to achieve popularity in China and other parts of Asia.

They were appointed cultural ambassadors, and in 2011 met the then Chinese premier, Wen Jiabao, in Tokyo.