CNN terminated its agreement with Griffin to appear in its New Year's Eve program in May, after her photo shoot in which she held up a "decapitated" head of President Donald Trump and was blasted both by the left and the right.
The two are touring the country, offering up "deep talk and shallow tales", for a show called AC2.
Cohen is the host of Bravo's "Watch What Happens Live", so he knows the hosting routine.
"I've been friends with Anderson for 25 years".
CNN announced Griffin would be fired from her hosting gig nearly immediately after the fake, bloody head photo went public.
Griffin, who had co-hosted New Year's Eve with Cooper since 2007, was sacked from the gig in May after her controversial photo shoot in which she posed with a bloodied replica of President Donald Trump's head. "It is going to be a blast!"
Cohen and Cooper will also likely be one of the few, if not the first, openly gay pair to co-host a New Year's Eve show. "We've travelled the world together and performed in 30 plus cities with "AC2" and it's all led to this one huge night!"