The pop singer, who had been supporting the Spice Girls during their UK stadium reunion tour, was reportedly suffering from “exhaustion” and unable to perform.
Festival organiser John Giddings appeared on stage to deliver the news to fans.
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A statement from her representative was also posted via the official Isle of Wight Twitter, which said: “Jess had every intention of performing today at Isle of Wight.
"However, as the show got closer it became apparent that she was physically exhausted after a very intense last few weeks of touring."
“As a result we took the decision to cancel the show. Jess is extremely frustrated and apologises to all her fans but ultimately her health must come first.”
Many angry fans posted on Twitter with reports of their children crying from disappointment at not seeing their favourite singer.
This is the second time Glynne has pulled out of Isle of Wight festival – the first time was in 2015 when she was forced to drop out after undergoing vocal surgery.
In May this year, she pulled out of her BBC Radio 1 Big Weekend performance hours before she was due on stage.
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