LOS ANGELES -- An airline says a Tokyo-bound flight returned to Los Angeles hours into the journey after the crew discovered that one of the passengers had boarded the wrong plane.

Model Chrissy Teigen was aboard and live-tweeted the developments. She wondered on Twitter why the plane was turning around four hours into the 11-hour flight.

A statement from All Nippon Airways says the pilot decided to return to the originating airport as part of the airline's security procedures.

Flight 175 left Los Angeles International Airport at 11:36 a.m. Tuesday and returned to LAX at 7:33 p.m.

ANA says it's trying to determine how the passenger boarded the wrong flight.

In an apology to inconvenienced passengers, the airline says it takes pride in customer service and failed on this flight.