Steve Carell is dimming the lights at “The Office.”

Carell, who’s played cringe-worthy Dunder-Mifflin boss Michael Scott on the NBC sitcom since its 2005 premiere, is filming his final episode, expected to air late next month.

NBC is keeping a tight lid on Carell’s swan song — and speculation has swirled about Michael Scott’s fate since Carell announced last fall that he was leaving “The Office,” which will air four more episodes this season after his departure.

What is known is that Michael has reignited his office romance with old flame Holly (Amy Ryan) — and that NBC has inked big- screen star Will Ferrell, who co-starred with Carell in “Anchorman,” for a four-episode arc.

Ferrell will play Scott’s ostensible replacement at Dunder-Mifflin — until it becomes apparent he’s not the right man for the job.

Possible Carell replacements include brooding actor Harvey Keitel, Will Arnett and Danny McBride.

There’s also the possibility that Carell won’t be replaced — and that Dunder-Mifflin’s new boss will come from within its own ranks.