The Wanted say they 'fear' for Nathan Sykes' voice
Siva Kaneswaran from The Wanted says the band fears Nathan Sykes might never sing again.
The star spent his 20th birthday having an operation for a haemorrhaged vocal cord in Los Angeles.
It is the same condition which Adele suffered at the end of 2011 and is usually caused by unstable blood vessels in the vocal cord that can rupture.
Siva Kaneswaran says they don't know how long he will take to recover.
The band - made up of Max George, Siva Kaneswaran, Jay McGuiness, Tom Parker and Nathan Sykes - say they'll carry on without Nathan for now.
"It takes a long time for the vocal cords to heal properly," he says. "If it doesn't heal in a certain way, it's going to take a lot longer.
"He might not be able to sing at all, who knows? You've just got to wait and see."
The Wanted have had number ones with All Time Low and Glad You Came.
They played their first gig since the star's operation in New York last week.
The singers are also working on their third album, with Nathan Sykes having recorded some his vocals already.
"Luckily we had a lot of these songs recorded before but there have been a few songs that have come in," Siva Kaneswaran explains.
The band have announced their next single will be Walk Like Rihanna.
It was one of the last songs Nathan Sykes was able to record with the band before having his operation.
"You can obviously hear in his voice something is difficult," Kaneswaran says. "All the other tracks we did after that he wasn't able to record and it's been quite difficult for him.
"What else can we do? You can't just click your fingers and bring the voice back, you got to just work with it."
"Our love goes with him and hopefully he will recover."
Follow @BBCNewsbeat on Twitter