British pop star Jessie J has been warned by doctors to tone down her live performances or risk aggravating her heart condition.
The Bang Bang singer was diagnosed with Wolff-Parkinson-White syndrome when she was aged 11.
Jessie J, now 26, limits her diet to help control the condition, which causes an irregular heart beat, but her doctors have urged her to slow the pace at her concerts amid fears the dancing and singing worsen her problems.
The pop star admits she often suffers bouts of ill heath on stage, but she is determined to continue singing live for as long as possible.
She tells Britain's The Times newspaper, "I don't know if I'm going to be in control to this as long as I want... (The condition affects me) more often than people think... You cover it up."
When asked whether her doctors tell her to change her shows, she adds, "Yeah, (of) course they do, and I just go 'Meh, this is what I do'... I have prided myself in having got this far without having to (lip-sync), but if my career carries on moving at the pace that it is, I will have to lip-sync to be able to stay well. My songs are so big."