Undead Nazi shooter Zombie Army Trilogy has called up the cast of Left 4 Dead and Left 4 Dead 2.
Francis, Rochelle, Nick, Louis, Ellis, Zoey, Coach and Bill are all now playable in Rebellion's game.
The characters have been added to the game in its latest free update.
And if you don't have the game already, Zombie Army Trilogy is 66 per cent off on Steam this weekend.
"We're delighted to be able to bring such iconic characters to Zombie Army Trilogy," Rebellion boss Jason Kingsley said. "As thrilling zombie shooters designed to be enjoyed with friends, Zombie Army Trilogy and Left 4 Dead share a lot of common ground.
"I'm sure fans of both series will enjoy what is a match made in heaven - or should I say hell! Also, I'd like to thank the team at Valve who've allowed us to use their characters in this way. It has been a blast working with them all - thanks for being so cool."
Two years ago there was a glimmer of hope that Valve was working on an official Left 4 Dead 3, although we haven't heard anything else since.
In the meantime then, here are the L4D heroes making a Reich mess of some zombies: