Forgive us if we're being picky, but that lipliner is just plain wrong. No?
The 'On The Floor' singer most certainly has 'a look' when it comes to her make-up.
Keeping her palette mostly to gold and copper tones, she is often spotted on the red carpet with warm smoky eyes, bronzed skin and nude glossy lips.
And there's absolutely nothing wrong with that. Those colours suit her complexion perfectly and, quite frankly, there's no-one we know who doesn't like to copy the J.Lo look during the summer months.
So, we're not sure what went wrong at the iHeartRadio Ultimate Pool Party in Miami Beach, Florida on Saturday (28 June).
Jennifer put in a killer performance at the event, singing and dancing her way through a number of tunes to promote her latest album A.K.A.
But her pout was anything but!
The rest of Jen's trademark hair and beauty look was firmly in place but her nude, glossy lips seemed to have been lined about an inch around the outside of her natural lipline.
Schoolgirl error – and totally unnecessary as the American Idol judge and mum of two has a pretty plump pout anyway.
Just look at the photo below taken a couple of months ago. Lips? Totally fabulous...
Maybe Jennifer's make-up artist thought no-one would notice.
But we did. Oops!
And if you're wondering how to make lipliner and gloss work much better together, simply follow the outer edge of your natural lipline and try lining your lips AFTER applying lip colour – this gives a much more natural finish.
What's your worst ever beauty mishap? Let us know below. Our fave comment across the site each week wins £50!
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