Hugh Henfer was caught in his birthday suit last night -- when the Playboy head honcho celebrated his 84th year of life.
Hef and GF Crystal Harris partied at the Palms Casino in Las Vegas Saturday night, starting with a dinner at N9NE steakhouse before headed to the Playboy Club.
The duo then headed to Moon, where we're told the entire club sang "Happy Birthday."
Never too old to party Vegas style!
