Benji Madden turned 29 with a bang on Tuesday as Hollywood heiress Paris Hilton threw him a glamorous party, complete with birthday gifts at LAX nightclub in Las Vegas.

Meanwhile, fellow socialite Nicole Richie, who dates Benji's brother Joel, reportedly threw a more low-key intimate bash for her man.

While the brothers busied themselves around town on Monday, Nicole was shopping in LA for party ideas, birthday gifts and other celebratory supplies.

Nicole and Joel have recently had a baby daughter called Harlow and as a result have been keeping out of the limelight, preferring cosy family affairs to Hollywood A-list parties.

Speaking to People magazine, Nicole described their life as "mellow" but claimed they wouldn't have it any other way.

Paris, on the other hand, known for courting the paparazzi, has been spotted out and about flashing a pendant with the letter B for Benji.

In return, Benji, a member of the band Good Charlotte, has been sporting a ring with his girlfriend's initials.