Kelly Osbourne had a lovely weekend lounging in the pool with her sister-in-law Lisa, however fans spotted a weird fluke in the sweet family picture which forced the reality star to post another Instagram picture to acknowledge it.

So what was this strange occurrence? Did a happy sting-ray pop up in the background? Perhaps Ozzy slipped over in the background slipped and fell in the pool? Or maybe, like us, you'll wrongly think it's because they're wearing the same kind of swimsuit.

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#SisterSunday #DivaLife with my sis @mrslisao #BestPoolDayEver 🤘🏼😂💜 A post shared by Kelly! (@kellyosbourne) on Apr 16, 2017 at 8:54pm PDT

Well no, actually everyone is in a flap about Kelly's tiny little baby arm that's poking out on the right hand side. The shrunken limb was spotted by fans after she shared the images with the caption:

"#SisterSunday #DivaLife with my sis @mrslisao #BestPoolDayEver."

Kelly then posted the picture again and circled the optical illusion after lots of people pointed out the hilarious mistake.

Check out my sexy baby arm!The most hysterical yet #epic #PhotoFail! This is instant karma For trying to hide my fat ass behind Lisa while holding my niece! 😩 A post shared by Kelly! (@kellyosbourne) on Apr 16, 2017 at 9:35pm PDT

She wrote: "Check out my sexy baby arm!The most hysterical yet #epic#PhotoFail! This is instant karma For trying to hide my fat ass behind Lisa while holding my niece!"

Lisa is the wife of Kelly's fellow Osbournes reality star Jack. The pair married back in 2012 and have two children, including the one that's hiding behind Kelly.

In other Osbourne family news, Simon Cowell has confirmed that matriarch Sharon is going to be returning to The X Factor judging panel along with Louis Walsh, Nicole Scherzinger and Simon himself.

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