Although details on Glenn Howerton's return to 'It's Always Sunny...' are a little sketchy at best, his absence - if you can call it that - is definitely noted in this poster for the thirteenth season of the long-running sitcom.

You've got Charlie, Mac, Frank, Dee and... who's that in the background? Why it's the Golden God himself, Dennis, coming out with a knife and a mask and finally confirming that theory that he's a serial killer.

As well as this, there was also a teaser of the supporting cast explaining what makes them afraid - in one case, it's the Waitress wondering if her and Charlie ending up together - which probably has something to do with how the twelfth season ended. 

'It's Always Sunny...' returns on September 5th and will likely be added to Netflix shortly after.