AceShowbiz -

Prepare for a bittersweet farewell with the beloved "The Office" characters. NBC will air an hour-long "retrospective" special at 8 P.M., which features the cast giving heartfelt commentaries abour the show, before the final episode featuring a big celebration begins at 9 P.M.

The series finale will jump forward six months after Dwight proposed to Angela in the penultimate episode to capture their wedding, which is previewed in a short snippet. Mindy Kaling's Kelly Kapoor and B.J. Novak's Ryan Howard are seen among the guests.

As the workers of Dunder Mifflin, past and present, gather for a wedding and a final round of interviews, mysteries are solved, hatchets are buried, pranks are prunked. Star John Krasinski promises that the episode will have a lot of "good surprises."

The series finale gets additional 15 minutes. Rachael Harris, Dakota Johnson, Joan Cusack and more are confirmed to guest star, while Steve Carell is rumored to return as Michael Scott for a cameo rather than a full-fledged guest appearance.