British rock band The Who has postponed the US leg of their 50th anniversary tour, after Roger Daltrey was diagnosed with viral Meningitis.

The Who had already postponed four dates due to Roger Daltrey’s “mystery virus”.

A statement on the band’s website said: “After extensive tests the seriousness of his condition became apparent.”

The statement added doctors had “prescribed rest”.

The Who apologized to fans and said Roger Daltrey was “on the mend”.

They said they had hoped The Who Hits 50! tour would go ahead, as Roger Daltrey was “getting better” and they did not want to inconvenience ticket holders, but the dates are now being rescheduled for Spring 2016.

“It wasn’t a decision taken lightly,” said the band.

“The Who always give their fans 100% and were never going to compromise the show, but ultimately the band had no alternative but to postpone the tour.”

The band said Roger Daltrey had been especially disappointed to miss the Teen Cancer America benefit in Los Angeles, a charity he and the band “have worked tirelessly for”.

“We are very sorry to disappoint our fans in this way,” Roger Daltrey said.

“For the last four weeks, I have been in and out of the hospital and have been diagnosed with viral Meningitis,” the singer revealed.

“I am now on the mend and feeling a lot better but I am going to need a considerable time to recover. The doctors tell me I will make a complete recovery, but that I should not do any touring this year.”

Pete Townshend also apologized to fans “that have supported us in the last 50 years”.

He added: “Once Roger is completely well we will come back stronger than ever and Roger and I will give you all a show to remember.”