Haley Joel Osment, Candace Cameron join FX's 'It's Always Sunny in Philadelphia' ... as a joke

There are big changes ahead for FX's "It's Always Sunny in Philadelphia," including an all-new cast! At least that's the surreal gag in the new promo for Season 8.

"The Sixth Sense" Oscar nominee Haley Joel Osment as Mac? Former "Full House" sweetheart Candace Cameron as Charlie? We can dig it. And so can the actual stars of "Sunny."

Check out the promo below and the Season 8 premiere of "Sunny" Oct. 11 on FX: