Somewhat grimy in appearance, it features a gold-colored blazer with a dark button-up collared shirt, slacks and lace up shoes. It appears the same on both male and female characters. Despite the fact that it somewhat resembles a suit, it grants no bonus to Charisma, Speech, or Barter like all other suits usually grant.
Viva Las Vegas is a 1964 movie starring singer/actor Elvis Presley and actress Ann-Margret. The New Vegas outfit is based on a costume Elvis wore in that film.
The outfit itself is a reference to the movie and song "Viva Las Vegas," having worn it while filming and subsequently performing the hit. The outfit is featured on the Collector's Edition playing cards similar to the promotional picture for the film with the same name, starring Elvis Presley.
Sometimes reverse pickpocketing doesn't work for any particular reason, even when giving the King a piece of clothing with higher DT. [verified]
Sometimes The King might be wearing some different clothing, meaning this won't appear in-game and you may have to revert to an older saved game. [verified]
Viva Las Vegas, as worn by the King on the Collector's Edition playing cards