The Karma Chameleon hitmakers are currently touring the U.S. with their original line-up for the first time in almost two decades, and they are due to return to the U.K. for a concert in the capital next month (Sep15).

However, frontman George reveals percussionist Moss is suffering a severe back problem and might have to undergo surgery.

The singer tells British magazine Event, "Jon... has back problems... Hopefully Jon will be better for the U.K. shows (sic). He may need an operation on his back."