Karan Johar threw a big bash for his 40th birthday, Prince William vacationed with his friends to celebrate turning 30 and Mariah Carey's kids had a big, fat first birthday bash at one of Paris' most luxurious hotels. See how these celebs celebrated their birthdays in style Prince William: Britain's future king hit the big 3-0 milestone on June 21. And to celebrate, his wife, the Duchess of Cambridge, arranged for Prince William to enjoy some high-octane water sports before they decamped with friends to a cottage they rented for the weekend.

Prince Azim: The third in line to Brunei throne turns 30 soon. And to celebrate, he invited some of the world's most iconic women to his birthday party at The Dorchester in London. Guests included Pamela Anderson, Mariah Carey, Jerry Hall and her daughter Lizzie Jagger, Glee star Matthew Morrisonand Gossip Girl actor Chase Crawford. In 2009, he throw 'The Party of the Year', where the flowers alone cost £70,000





















Sir Philip Green: The fashion billionaire, who owns the Topshop chain of stores, threw a £6 million party to celebrate turning 60. Green flew friends, including Simon Cowell, Ronnie Wood, Leonardo DiCaprio, actress Kate Hudson, Kate Moss and Naomi Campbell, to the Rosewood Mayakoba Resort in Mexico for four days; threw two fancy dress parties and even had a nightclub specially erected for his daughter Chloe. Oh yeah, and Robbie Williams and Steve Wonder performed.









Mariah Carey's Kids: The pop star's twins Moroccan and Monroe, turn one with a big, fat party in Paris. Mariah pulled out all the stops to organize a diva-worthy party for her son and daughter at the uber-luxurious Plaza Athenee . Gifts for the babies included a baby grand piano, a rocking horse and a toy Ferrari car. Guests nibbled on custom-made French pastries.