Actor Dylan McDermott went back to his roots as a cocktail waiter to prepare for his role as a TV mob boss.The American Horror Story star grew up in New York and perfected his cocktail-making skills while trying to make ends meet as a struggling actor, and he has admitted his experience at the bar helped him get under the skin of the organised crime boss he plays on U.S. series Law & Order: Organized Crime, explaining he often served people just like his latest tough-guy character."I used to bartend so they would come in," he recalled on U.S. show Live with Kelly and Ryan. "It was, like, four o'clock in the morning (and) you're closing up. I'm like, 'Sorry guys, we're closing up', and they'd be like, 'No you're not'," he went on.The star recollected that the apparent mob members easily persuaded him: "And I'm like, 'OK, sure, whatever you guys want'. I would stay open until whenever they wanted to leave."Law & Order: Organized Crime, a spin-off of Law & Order: Special Victims Unit, premiered in the U.S. earlier this month. In the show, McDermott plays Richard Wheatley, a businessman and owner of an online pharmaceutical company who moonlights as a crime boss with mafia ties. He's considered a suspect in the murder of the wife of the show's lead detective, Elliot Stabler, played by Christopher Meloni.