Kelly Osbourne's dog once pooed everywhere during a flight.

The 31-year-old star regularly flies with her beloved pet Pomeranian Nancy and on occasions with her other mutt Sid because she hates to be without her canine chums.

Kelly is adamant that other plane passengers can travel without the fear of an in-air emergency doggy defecation because they're so well trained but she has had to confess that there was one time when Nancy had an accident in her seat.

Kelly was quizzed by TMZ at Los Angeles International Airport as she walked through the lobby with Nancy about the pooch's toilet habits.

The videographer asked: ''How do the other passengers feel if your dog has to take a dump on the plane?''

To which Kelly answered: ''Well ... No, no, no, she's very well trained.''

The cameraman then said: ''Have you ever seen other people's pets get messy?''

Prompting the 'Project Runway: Junior' judge to confess: ''I don't think I ever have. Although one time I was on a flight to Miami and my dog s**t all over the plane! That is the truth.''

Kelly is besotted with her four-legged friends Sid and Nancy - named after ill-fated lovers, late punk rockers Sid Vicious and Nancy Spungen - and regularly buys fancy clothes and treats for them.

However, the two dogs don't always get on with each other and Kelly - whose parents are Sharon and Ozzy Osbourne - often has to separate them at dinner time otherwise Nancy eats all of Sid's food.

She previously revealed: ''Nancy loves food so much I have to feed Sid on the couch! She won't leave him alone!''