The Godfather star celebrated the milestone anniversary by taking 15 of his pals to Sin City nightspot The Bank, and knocked back potent shots while surrounded by a bevy of beauties, according to the New York Post's PageSix column.
And he caused such a stir while trying his luck in the casinos, extra security had to be drafted in to provide him with some privacy.
However, Caan's soon-to-be-ex-wife Linda Stokes didn't enjoy the party as much as her estranged husband. A source tells the publication, "They didn't speak much."
Caan, who shares two children with Stokes, filed for divorce last November (09), citing irreconcilable differences.