He hoped he would well enough to perform tonight in Newcastle but the Sligo native is still not in top form
Mark had to pull out of a major gig at the last minute after he had come down with a fever.
He hoped he would well enough to perform tonight in Newcastle but the Sligo native is still not in top form.
The quartet arrived in Newcastle after a sell-out show at Manchester's AO Arena on Thursday evening but there was a blow to fans as Mark didn't join Shane Filan, Nicky Byrne and Kian Egan for Friday night's gig.
Westlife gave their fans an update on Instagram.
They said: "Hi everyone. Unfortunately, under strict doctor's orders, Mark is still unable to get back on stage for tonight's show in Newcastle.
"The party will still go ahead and although we are all gutted he can't be there, he sends his love as always and hopes you all have the best night ever.
"Love, the boys x."
Mark added: “I'm so sorry to tell you I won't be able to join the boys on stage tonight in Newcastle.
"I felt really feverish last night after the Manchester gig, then the same again this morning but a whole lot worse - been with the doctor and he says there's no way in the world I should do the show tonight."
Westlife fans took to the comments to wish Mark a speedy recovery from his mystery illness.
Sally commented: "Absolutely gutted but you have to put yourself first Mark, get well soon."
Jana said: "Sending all my love to Mark for a quick recovery!"
Samantha wrote: "Awww hope you feel better soon Mark."
Sarah commented: "Sending Love mark. Will miss you, get well soon."
This comes after Westlife fans were left open mouthed as Nicky Byrne showed off their bizarre stage trick
The singer took to Instagram yesterday to share a video of how they make their custom in-ear monitors.
The custom-made monitors ensure a secure fit while the artists are performing on stage.
The Dublin said: "New ear monitors being cooked."
In the video, Nicky got green mould put into his ear to make an exact impression of it.
The waxy-like silicone substance was then pulled out of the 44-year-old's ear while he bit down on a sponge.
The clip was a little squeamish and fans thought it looked painful.
One fan commented: "Looks really hurtful."
Another said: "That looks painful and uncomfortable and is giving me the heebie jeebies lol."