[Guess] Spot the object that appears twice!

It is going to be a bit different for today's guess post!

Well,you are not required to guess the star appeared in the photo but this post is going to test your eye sight.

The photos above show the album cover of SNSD's "Oh!" and f(x)'s "Chu',there is an object appeared on the member of both groups,can you spot the similar object??

For those who already know the answer,please don't reveal it,thanks!

Credits to Roseraphix @ Soompi for the photo!