The 'Smile' singer, 29, was storming the stage at Hylands Park, Chelmsford on Sunday, 18 August dressed in a slashed-to-the-naval silver catsuit.
While she certainly looked fab, it seems the zipper on her jumpsuit was lowered just a bit too much as she ended up flashing her nipple at the crowd.
Not that we're sure any of the thousands of people watching her set in Essex could really see from a distance…
And perhaps skintight leather wasn't the best choice for beneath the harsh stage lights, as she ended up disappearing backstage for a few seconds to yank her jumpsuit down to her waist before reemerging, insisting it hadn't been planned.
Wardrobe malfunction aside, the star put on an AMAZING show, belting out hit songs including 'Smile', 'LDN', 'Not Fair', 'The Fear' and 'Somewhere Only We Know'.
The crowd were massively responsive, dancing and singing along as she performed on the main stage just ahead of Paolo Nutini and The Killers.
One thing's for sure with Lily Allen, she definitely knows how to put on a good show!
Lily's appearance in Chelmsford was her FOURTH festival appearance in just a week after performing at Weston Park and over in Vienna and Budapest.
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