The official trailer for Season 18 of "It's Always Sunny in Philadelphia" has confirmed the return of filmmaker Guillermo del Toro as the repellent patriarch Pappy McPoyle, alongside the return of the McPoyle family more broadly. The trailer teases another chaotic run for the FX sitcom, following on from last season's crossover with "Abbott Elementary" and the reappearance of long-running nemesis "The Lawyer".

The new season opens with the fallout from last year's finale, in which Frank (Danny DeVito) proposed to Sam (Carol Kane); the premiere episode, titled "Frank Marries a Corpse," suggests the wedding will not go smoothly. Other storylines glimpsed in the trailer include the Gang disrupting a Renaissance Faire with guest star Nick Kroll, a school-set plot, a baseball game, and a chase involving a non-alcoholic beer salesman. Season 18 premieres with a two-episode debut on FX and Hulu on 17 August.