The singer released a statement on social media this evening to confirm he won't be performing at the band's upcoming concerts in North America.
He wrote: "Hello and much love to you all! It's Mark here.. Most of you are aware that I have had some health challenges over the past while. It actually all started 3.5 years ago in August 2020 when I had surgery. Within a few days of this surgery I was in severe pain and was rushed into A&E.
"That surgery took place recently and thankfully it went according to plan but with that, my recovery must now become my absolute priority at this time. It is with the upmost level of regret that I must now temporarily stand down from all Westlife touring until a time that I have had the chance to fully recover from the turbulent journey I have been through as an individual.