Robert De Niro, who famously called himself the best actor he's ever worked with, goes to war with another Robert De Niro in the trailer for the upcoming biographical crime thriller The Alto Knights.

Robert De Niro portrays two real-life mob bosses, Vito Genovese and Frank Costello, in the trailer for Barry Levinson's movie 'Alto Knights,' out March 21. The movie also stars Cosmo Jarvis, Debra Messing and Kathrine Narducci.

Robert De Niro is starring as the Mafia boss in a mob drama. Sounds about right. But this time, he’s playing both lead roles: Vito Genovese and Frank Costello. De Niro will double his acting expertise in The Alto Knights, a crime drama inspired by the true story behind Costello and Genovese’s deadly rivalry.

Jan. 14 (UPI) -- Warner Brothers is previewing The Alto Knights, starring Robert De Niro as both Frank Costello and Vito Genovese. The movie is about the power struggle between the iconic gangsters. The trailer shows the pair meeting in a dark restaurant in an apparent hotel.

The official trailer for the Barry Levinson-directed film, which arrived Tuesday, shows the Academy Award winner in a dual role, in which he portrays two of New York's most notorious organized crime bosses, Frank Costello and Vito Genovese.