Crystal was wracked with nerves as he prepared to shoot his scenes for the Shakespeare tragedy, because he feared he wouldn't be able to shake his New York accent, and would stand out for all the wrong reasons.

So the filmmaker came up with a quirky way to make Crystal feel comfortable as the First Gravedigger - by urging him to do an impression of De Niro from 'Taxi Driver', while Branagh, who portrayed the titular Danish prince, put on his best Joe Pesci voice from 'Goodfellas'.

"I was the gravedigger in 'Hamlet', and it was the scariest thing I've ever had to do," Crystal told U.S. talk show host James Corden. "I have this little Bronx voice... and you know, it's Shakespeare, the great Branagh, and I'm playing the gravedigger and I have to give him the skull so he can say, 'Alas, poor Yorick! I knew him well, Horatio'. It's an incredible responsibility.

"(Branagh) called me and said, 'I want you to play this part.' Jack Lemon was in it, Derek Jacobi, Robin Williams was in it, so we're all there and he says, 'Let's rehearse the day before shooting...'

"He says to me, 'Billy, get in the grave, but you're Robert De Niro and I'm Joe Pesci and that's how we'll rehearse the scene.' He wanted to relax me, so I'm picking up skulls as Robert De Niro, going, 'Are you talkin' to me? Look what I did to you...!' He was hilarious (as Pesci). He was like, 'Do I look funny? Is this funny to you?' We rehearsed and it really relaxed me. The next day I shot my stuff and it was a remarkable experience."