Both groups have scheduled their new albums' release for the same day of November 21.
Westlife will unveil their new Greatest Hits collection after defecting from Simon Cowell's Syco label earlier this year and joining Sony division RCA.
Meanwhile, Cowell has announced that his new boyband and X Factor finalists One Direction will release their highly-anticipated debut album in the same week.
The pop teens are currently number one in the UK singles chart with their new song 'What Makes You Beautiful', which became the fastest-selling single of the year so far.
Cowell has reportedly laid down plans to take One Direction to America and sign a US record deal.
Westlife are currently in Africa filming the music video for their new single, which has been written by Take That's Gary Barlow and songwriter John Shanks.
> One Direction interview: 'We're nervous over number one single'
Watch the music video for One Direction's number one single 'What Makes You Beautiful' below: