Crowe said Luke was arguably the strongest man, pound-for-pound, at the club.
Crowe, a keen student of boxing, gave him the same advice he gave heavyweight legend David Tua.
"It is from [Muhammad Ali's boxing trainer] Angelo Dundee, about the importance of conditioning your body: 'If you can breathe you can think, if you can think you can win.'
"That old Ali quote, about what you don't do in the cold light of dawn becomes very clear in the hot lights of the ring, should be the mantra of anyone contemplating a bout.
"Personally, I don't know why [Luke] wants to box. I can understand the charity aspect, but he's got nothing to prove by doing this and neither has his opponent."
Crowe said he was "old school" when it came to boxing and didn't approve of those who took part in the sport for fun.
"Boxing has to be about essentials. The man who has to fight to feed his family, the man who has to fight because there's no other path open, the champion who has to rise from the ashes because there are moral and political perspectives, that only victory will underline for history to record.
"Boxing means nothing if you are just mucking around."
Crowe, 47, is in Vancouver filming a new Superman movie, in which he plays the superhero's biological father, Jor-El. Organisers hope he will attend the bout on December 3, at the Trusts Stadium in Waitakere.
Luke, who was named in the 23-man Kiwis squad for the upcoming Four Nations, will line up alongside Monty Betham and Awen Guttenbeil in the Fight For Life bout.
The Four Nations final is scheduled for November 19 - just two weeks before the Fight For Life bout.
Organisers were yet to speak to headliner Jonah Lomu, who remains in Auckland City Hospital with complications from his liver transplant and is in doubt.