Justin Timberlake and Cameron Diaz threw a party to celebrate their year-old relationship.

More than 20 friends gathered at a £6,900 per night penthouse at Las Vegas' Hard Rock Hotel for the occasion. The partygoers enjoyed a meal from Nobu restaurant before moving on to the hotel's Peacock Lounge where they gambled into the early hours, according to the New York Post.

Among the guests was Timberlake's mother, Lynn Harless, although she is reportedly none too keen on the pair's relationship.