The Sligo star has had to pull out of the Westlife tour after catching pneumonia.
The Sligo singer has been ruled out of a number of shows on Westlife’s UK tour as he fell ill two weeks ago.
"I’m slowly going bonkers being away from the tour and just staying in bed all day,” the boyband star said as the thanks fans for their support.
"But I want to be back on stage ASAP and the doc is telling me to be patient and recover 100% so I can move on and put it all behind me,” he told followers on Instagram.
“Lots of love to you all. Hope to see you soon."
The singer paired his update with a video, showing a weary looking Mark waving to the camera from bed before it switched to his bandmates on stage in front of a venue full of fans.
In a tribute to the band – who have had to continue the tour without him – Mark’s own song Miss You Most (At Christmas Time) played in the background of the clip.
Fellow Irish pop star Nadine Coyle took to the comment section to send some well wishes: “Aww Mark!!! I hope you are feeling better soon!!!”
Westlife member Kian Egan added: “It won’t be long Markie...”
The band have had to get creative as they wait for Mark's return, even bringing a cardboard cut-out of him on tour in Liverpool.
Fans found the move hilarious as Nicky Byrne shared clips of the band carting the fake Mark around on stage.
Mark had issued a health update to concerned fans earlier this week, explaining why he was taking a break from touring under strict doctor’s orders.
After feeling “feverish” in Manchester, the Sligo singer had been told to let Shane Filan, Nicky Byrne and Kian Egan go on without him.
"I know it’s scary when you first hear the word ‘pneumonia’ but thankfully I got to the doctor and hospital very quickly and got on the antibiotics as soon as possible, so everything is under control,” he told Instagram followers.
"I have been informed that the quickest way to recovery is to rest and continue the antibiotics. I’m feeling a bit better every day.
"The nurses and doctors are taking amazing care of me so it should be all over in no time.
"This does however mean missing more gigs which is horrible but I’ll be back on stage as soon as I get the all clear.”
The star said his bandmates “will continue to fly the Westlife flag high for all of us.
"Please scream even louder than usual for those three legends in my absence!”
The Sligo star thanked followers for their well wishes and said he hopes to see them “back on the road very very soon.”