Though reports are a little sketchy on what actually went down, it doesn't look like the stunt was planned or set-up by the comedienne for laughs.
Just witnessed someone throw cake in Joan Rivers face omg— Sydney Goldstone (@syd_gold) March 1, 2014
So who caked Joan Rivers? Here's the celebrity line-up as we imagine it.
Did Adele cake Joan Rivers?
Joan has famously criticised Adele's weight, so did the 21 singer finally get her own back?
Did Jennifer Lawrence cake Joan Rivers?
Jennifer Lawrence and Joan Rivers have been locked in a media spat over weight criticisms, Fashion Police attacks and public retorts. Did JLaw finally have the last word?
Did Miley Cyrus cake Joan Rivers?
Most of what Joan Rivers has said about Miley Cyrus isn't far off the mark, but did the singer twerk her way onto the red carpet with cake in hand?
It could also have been any of these happy Twitter people, or pretty much anyone in Hollywood last night...
What do you think about Joan Rivers getting caked? Tweet us @handbagcom
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