Product endorsement is a big responsibility for a celebrity when they're getting free stuff in return, but Jennifer Lopez seems to have forgotten that because she is now being sued for more than $50K after failing to promote a hoverboard company on social media despite their contractual agreement.

Jennifer Lopez seen at the NBC Press DayJennifer Lopez seen at the NBC Press Day

Back in 2015, J-Lo signed a deal with Sidekick Group that she would namedrop them on Instagram and Twitter every three months in exchange for no less than 42 custom-made SideKick Wheels to be used by her backing dancers during her 'All I Have' Las Vegas shows. 

However, it seems the 'Ain't Your Mama' singer only made the one reference to the company, and that was back in May 2016 when she posted a video fo her dancers using the boads during her performance of 'Love Don't Cost a Thing' at Planet Hollywood - four months after she began her Vegas residency.

'The #AllIHave dancers killing it on their @SideKickWheels', she wrote. 'Check them out at http://www.sidekickwheels.com #JLoVegas'.

That wasn't quite enough for SideKick, who are now demanding $54,390 from the singer which is the actual value of all the Wheels, with their retail price at $1,295 each at the time of the agreement. So far, J-Lo hasn't responded publicly to the backlash.

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She's not the only high-profile celebrity who has failed to live up to product endorsements. Kourtney, Khloe and Kim Kardashian were all sued for millions last year by Hillair Capital Management for failing to promote their own Kardashian Beauty line. It was a rather complicated case, but the sisters went on to counter-sue for unpaid royalties and use of their image after the licensing agreement had been terminated and ended up winning.

We don't know what Jennifer Lopez is going to pull out of the bag to get out of this one, but it could get interesting.