Kelly Osbourne was refused entry to a casino because the security guard believed she was underage.

The 'Fashion Police' star wanted to enjoy a night out at the Star Casino in Sydney, Australia, but her plans to hit the roulette table were scuppered by the over-zealous staff member.

Even though Kelly showed security guard ''Sam'' her ID to prove she was older than 18 - the legal age to gamble Down Under - he didn't accept her proof of age and left her exasperated.

In an angry Twitter post, the 28-year-old star revealed: ''In disbelief at how rude the security guard 'Sam' at the Star casino AU was to me & my friends for NO reason he is a first class tw*t!

''All I did was show him my ID to get into the casino he called me a liar & treated me like i was a criminal! (sic)''

Kelly's disastrous casino trip has been the only blight on a fantastic trip to Australia where she has taken part in a glamorous photo shoot and done a host of interviews.

However, the star was dealt some bad news when she discovered her mother Sharon's favourite dog has died.

Japanese Chin Maggie - who shot to fame with the rest of the family on MTV reality series 'The Osbournes' - passed away last week and Kelly is devastated at the loss of the beloved family pet.

Writing on her Twitter page, she said: ''Woke up to the worst news ever! I can't stop crying! It really is an end of an era RIP Maggie!!!''

Sharon and her husband Ozzy have been living apart for the past few months after the Black Sabbath rocker fell off the wagon and started using drink and drugs again. However, he is overcoming his substance abuse issues and has been sober for over 40 days.