Welsh Opera singer Katherine Jenkins has revealed that she sleeps with her eyes open, due to a condition she has lived with since she was a child.
Ms Jenkins,33, suffers from Nocturnal Lagophthalmos, which means sufferers are unable to close their eyes fully when they sleep.
"My eyes don’t close properly - they are always at least half open - and when I go to sleep I look like I’m still awake," she said in a recent interview.
"And I don’t really have dreams either. My mum would always say: 'Katherine, are you awake or are you asleep?’"
Lagophthalmos can be caused by factors including facial paralysis, stroke, infection, trauma and surgical procedures.
Sufferers can treat the condition by using an ointment at night or by taping their eyelids closed with surgical tape, although use of ointment may cause blurry vision and surgical tape can cause skin irritation.