Dean Martin, nicknamed Dino, was a popular singer and comedic actor, as well as a legendary Las Vegas entertainer during the 1950s and 1960s. So much, in fact, he was included in the holosuite program Bashir 62, a 24th century rendition of 1962. At the time, Martin was good friends with Frank Sinatra, Sammy Davis, Jr., Joey Bishop, Peter Lawford and was incorporated as a personal friend of Vic Fontaine's. Dean often served as fodder in the many stories included in Vic's programming.
Fontaine once recalled to Odo that Martin and Sinatra dropped in on him once while he was playing at the Sands Hotel back in 1958. Together, the three of them took over one of the blackjack tables and dropped a combined $15,000. (DS9: "His Way")
While playing cards with his band one night, Fontaine recalled another story about Martin and Sinatra, which Fontaine revealed mid-story "...but this time he's switched all the robes in the steam room. So when Dino goes to pick up his robe, he doesn't realize that across the back, Frank has printed in big bold letters...", but did not finish, as he was interrupted by Ezri Dax. (DS9: "It's Only a Paper Moon")