08/17/2011 AT 06:00 AM EDT
As he counts down the days until his nuptials
to Kim Kardashian
, NBA star Kris Humphries
hit up the SkyBar at L.A.'s Mondrian Hotel for the monthly Champagne & Caviar party with five of his guy friends. Humphries sat back and enjoyed a Grey Goose and soda while his friends chatted up female partygoers. Days before the guys' night out, the athlete and his buddies went shopping at Santa Monica Place. Says an onlooker of the groom-to-be: "He seemed super-relaxed and calm."