S Club 7 member Paul Cattermole died at the age of 46.
The band shared the heartbreaking news on Twitter, expressing their grief and loss.
The cause of Cattermole's death is unknown at this time.
S Club 7 has announced a 25th anniversary reunion tour in the United Kingdom.
In 2000, the group won the BRIT Award for best newcomer and had several UK No. 1 hits.
Cattermole left the band in 2002 to join a heavy-metal band, Skua.
In 2008, he went on tour as S Club 3 with O'Meara and McIntosh.
All seven bandmates reunited for a comeback UK tour in 2015.
Cattermole auctioned off his 2000 BRIT Award on eBay in 2018.
He suffered a back injury while performing and found it hard to find work in the entertainment industry.
He hoped to use the eBay money to pay bills and potentially record a solo album.