The entire members-only club was rented out for the event, according to E! News, with invitees feasting on hors d'oeuvres including mini crab cake burgers, tuna tartar bites and freshly-baked chocolate chip cookies.
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Leonardo DiCaprio celebrated his 40th with friends including Jonah Hill
Birthday boy Leo arrived around 11pm, by which time the party was in full swing, and made sure he spent time socialising with all his guests.
The Hollywood heavyweight stayed at the party until around 1.30am, then headed to a private house to continue the celebrations.
There was one noticeable absentee on the night – Leo's model girlfriend Toni Garnn. Her Instagram account revealed that she is currently out of the country, working in Berlin.
Leonardo DiCaprio and guests partied at Soho House in West Hollywood
Leo spoke earlier this year about reaching the big 4-0. "I suppose 40 represents something different, but I've been thinking about being 40 for so long that I'm prepared for it," he told Shortlist.
"It seems like the age barometer where you're still considered youthful is getting higher and higher. I'm going to hold on to that ideal as long as I can."