Fallon announced the project on Thursday's edition of The Tonight Show Starring Jimmy Fallon.
"Lip sync battling is one of the coolest things happening in pop culture right now and already has a huge fan base thanks to the amazing talent involved," Casey Patterson, executive vice president of talent development and production for Viacom Entertainment Group, said in a statement. "We're thrilled to be in business with producers as talented as Jimmy, John and Stephen as Spike broadens its programming in new and exciting ways."
Each Lip Sync Battle episode will feature celebrities going head to head, lip synching the song of their choice, Spike TV said.
Along with serving as executive producers, Fallon, Krasinski and Merchant will appear and perform on Lip Sync Battle. The series will tape in January in New York City and will premiere on the network April 2. The show's host and a list of the talent who will be battling will be announced in the coming weeks.