Zooey Deschanel Files for Divorce -- We Broke Up on Halloween

1/4/2012 3:54 PM PST

Zooey Deschanel Files for Divorce From Ben Gibbard

Zooey Deschanel
has decided to end her marriage ... two months after separating from her rock star husband Ben Gibbard ... TMZ has learned.

The "New Girl" star filed the divorce docs in L.A. County Superior Court on December 27 -- blaming the split on "irreconcilable differences."

She also lists the official date of separation as October 31 ... Halloween.

Deschanel and Gibbard -- lead singer for the band Death Cab for Cutie -- were married in 2009. They have no kids.

For some reason, Zooey's lawyer attached the singer's income and expense declaration ... and she's both filthy rich and shockingly thrifty.