Marina And The Diamonds has revealed she is "distraught" about having to postpone her UK shows, on "urgent doctor's orders".
Marina Diamandis announced that the tour, which was due to start in London on May 3, will be rescheduled to June after doctors advised her not to sing until the end of May.
In that time she will undergo treatment for a damaged vocal chord.
"It is with huge regret that I have had to postpone my UK tour dates due to medical advice," she said in a statement to fans.
"I have been experiencing vocal problems for three weeks now and consequently today, the doctor has told me that I cannot sing performance length shows while I undergo treatment, or I could cause permanent damage to my vocal chords."
The 26-year-old singer, whose second album Electra Heart is released this week, added: "I am distraught as I was so looking forward to seeing you all on The Lonely Hearts Club tour. I hope you understand that not being able to play for you in May is very upsetting."
All the dates except the Live At Leeds festival have been rescheduled, starting from June 18.
"I promise that these shows will be the best I have ever performed for you, as hopefully I will be 100 per cent healthy!" she continued.
"All existing tickets will be valid for the new dates and I also promise my Leeds Diamonds that I will see them in the autumn."
More details about the postponed shows can be found on her website, www.marinaandthediamonds.com.