AceShowbiz - Demi Lovato has cancelled her concert in England hours before she was due to hit the stage.

The Cool For the Summer hitmaker was scheduled to perform in London on Sunday, June 10 at The O2 Arena, but she has now taken to social media to announce she has swollen vocal cords.

"I write this through tears of frustration and sadness that I have to postpone my concert in London at the O2 tonight due to being very, very sick and with swollen vocal chords (sic) that were examined by an ENT (ear, nose, and throat doctor)," she writes in a lengthy message on Twitter. "If I go on tonight and injure my vocal chords anymore I could potentially have to cancel the rest of my tour".

"I'm so so so sorry to disappoint any of my fans in London that have traveled hours to be here by plane or car, and to all of the fans that got these tickets for their birthday, holiday or any other special occasion," she continues. "It breaks my heart to let you down".

💔 pic.twitter.com/Rs7ZWMCvcQ

— Demi Lovato (@ddlovato) June 10, 2018

Demi went on to reveal the show has been rescheduled for later this month.

"Just know I feel your frustration and I wouldn't do this unless I absolutely had to," she adds. "For everyone who bought a ticket to tonight's show, I will see you for the rescheduled date on June 25th after Madrid and Rock in Rio. Thank you for understanding. I love you".

Demi has also posted an apology video on Instagram Stories.