The actor - who is now starring alongside Imelda Staunton in a West End version of 'Sweeney Todd' - previously played the role in the original London cast of the musical, and with Eddie set to take over the part of the student revolutionary for the forthcoming film adaptation, the pair have sat down and discussed the part.
He told The Daily Telegraph: ''I saw Eddie at Buckingham Palace and we had a long, long chat about the part.
''He doesn't need any of my advice; he's a phenomenal actor with a great singing voice. He was just really flattering about having seen it an anxious to do it Justice, so I told him all the things I thought might help.''
Eddie - who is also a model for Burberry - has previously revealed he was nervous about singing in the role.
He told BANG Showbiz: ''I am singing! I would be lying if I said I was completely cool with it. But I did sing a bit as a kid and my parents took me to see that play when I was younger - it's amazing what a following it has, and so many avid fans.''
'Sweeney Todd' - which tells the tale of a barber on a killing spree to make pies out of human flesh - is now running at the Aldelphi Theatre on The Strand.
The production has attracted rave reviews and already been seen by a host of stars including singer Sir Tom Jones, 'The Iron Lady' star Jim Broadbent, presenter Richard Madeley and comics David Mitchell, Jason Manford and Frank Skinner.