All Saints are reforming in 2014.
The 'Never Ever' hitmakers - who first parted ways 12 years ago - have announced they will be supporting the Backstreet Boys on tour during their five UK dates next Spring.
The British girl band said in a statement: "We are really looking forward to performing together as guests of the Backstreet Boys on their tour. We can't wait.
"We're singing a lot of big songs like 'Never Ever' and 'Pure Shores' which will be amazing."
All Saints were one of the most popular pop groups of the 90s, scoring a string of top ten hits after rising to fame in 1997.
The quartet - formed of Shaznay Lewis, Melanie Blatt, Natalie and Nicole Appleton - split in 2001 due to rumoured rifts between members, before briefly reforming in 2006.
The news comes as a surprise since Melanie had insisted back in August 2009: "All Saints are never getting back together again. I never want to sing again. I recently did the Brits with Nic and we just went round chatting to people and then got drunk. That's my goal - to get paid for chatting to people and getting drunk!"
The tour, which kicks off in the UK in Birmingham on March 6, 2014, also marks a comeback for the girls' 90s pop rivals the Backstreet Boys, who will be performing together as the original line-up for the first time in 10 years thanks to the return of Kevin Richardson.
All Saints will be supporting the Backstreet Boys on the following dates:
March 6 - Birmingham, LG Arena
April 1 - Dublin, The O2
April 3 - Glasgow, Hydro
April 4 - London, The O2
April 5 - Manchester, Phones 4u Arena