There was just one thing missing from Cher’s performance at the Billboard Music Awards – her right nipple.

Yep, welcome to the case of the missing nipple.

As the Believe star performed her classic hit on Sunday night, fans noticed something about her boobs.

The 71-year-old's left breast was covered by a glittery nipple sticker and her right one was not.

And well... it was nowhere to be seen.

We repeat, her nipple was nowhere to be seen. 

Thankfully, some very cluey armchair detectives Twitter users immediately got on the case and started #operationfindchersnipple.

Can you BELIEVE this performance?!?! ???? @cher is OWNING the #BBMAs stage rn. #IconCher pic.twitter.com/LXQhSWl00z

— BillboardMusicAwards (@BBMAs) May 22, 2017

Was Cher's nipple blurred out? Was she wearing a nude nipple pasty? Does she have a right nipple? Was her nipple abducted by aliens?

#BBMAs WHERE IS CHER'S OTHER NIPPLE COVER. AND WHERE IS THE NIPPLE

— Taleigha???? (@Tal_Hunter) May 22, 2017

Where was #cher s nipple I don't freaking understand where it went #bbmas

— Kimberly Webb (@kimberlywebb_) May 22, 2017

Are they blurring Cher's other nipple out or what's going on? I'm confused

— Andrea (@andreeaaa_z) May 22, 2017

LISTEN: Are your nipples in fashun? Post continues...

If you ask us, a nude-coloured sticker is definitely to answer for.

We may never really crack the case of Cher's missing nipple - but with an outfit like that, we guess it was Cher's aim to make the internet explode.

And boy has she succeeded.

What's your take on NippleGate?