A UNITED passenger was in some deep doo-doo after smearing feces in the plane — causing the Chicago-to-Hong Kong flight to divert to Anchorage, according to reports.

Flight 895 took a crappy turn Thursday night when the man smeared excrement inside a couple of bathrooms, removed his shirt and tried to shove it into a toilet, KTVA reported.

FBI agents and Alaska’s Ted Stevens International Airport police met the poopy passenger, who had cooperated with flight attendants after the foul episode aboard the Boeing 777.

Airport police said the man was taken to hospital for a psych evaluation. No charges were immediately filed.

The soiled aircraft was grounded to undergo a thorough wiping, according to the news station.

This isn’t the only feces-related incident to force an airliner to land prematurely.

A Delta flight was forced to make an emergency landing in Montana in December to accommodate passengers who needed to go potty after the aircraft’s bathroom failed to function.

(SD-Agencies)