The Hollywood veteran agreed to portray real-life union official-turned-mafia hitman Frank 'The Irishman' Sheeran in the biopic back in 2010 and shooting was expected to start the following year.Scheduling issues have meant that cameras have yet to start rolling on the movie, but De Niro is refusing to give up on reuniting the Goodfellas clan.He tells art magazine Flatt: "We have been trying to do (the film) for the last few years, and I think we will do it."That's something I'm looking forward to very much. I think it will (happen). We're really working towards making it happen."The Irishman, De Niro and Scorsese's first film together since 1995 crime classic Casino, will be based on author Charles Brandt's 2004 book I Heard You Paint Houses, in which Sheeran detailed his alleged murder of mafia leader Jimmy Hoffa.