Inside Leonario DiCaprio's 40th Birthday Party

Celebrating the big 4-0 Tuesday night at Soho House in West Hollywood, Leonardo DiCaprio was surrounded by friends and former costars, including Tobey Maguire, Jonah Hill, Robin Thicke, Kevin Connolly, Tyrese and Adam Levine. "Leo made sure the party had started by the time he arrived around 11 p.m.," says a source at the bash, which drew about 100 people.