Paul Gallen didn't mince words when asked about the greatest fear heading into his boxing debut on Saturday night.
''Getting knocked out by a 115kg monster,'' said the NSW and Cronulla skipper, who will swap footy boots for boxing gloves in the name of charity.
Gallen will go up against Hika Elliott, part of a rugby league versus rugby union 'Fight for Life' event in Auckland that also includes NRL stars Willie Mason, Greg Bird and Manu Vatuvei.
The Sharks hardman admitted the nerves were starting to take hold as he headed into the great unknown.
''I'm nervous, no doubt about it,'' Gallen said.
''On the footy field I put myself in this position every week of possibly getting myself knocked out, but I've been doing it since I was six years old so I know what to do when I get in certain circumstances, I feel comfortable out there.
"This is an arena where I don't know what to do.''
Mason, who recently re-signed with Newcastle for two more years, said the boxing ring can feel like a lonely place.
''We all feel safe on the footy field, you've got your mates there backing you up,'' he said.
''But we're all well aware that you are by yourself in there.''
Gallen's fears haven't been helped by reports Elliott, an All Blacks hooker who plays with Super Rugby champions the Chiefs, is an experienced kick-boxer who also holds a black belt in kung fu.
Still, the prospect of an ugly mismatch hasn't stopped Gallen getting ribbed by his mates.
''(Sharks teammate) Ben Pomeroy's come up with the best line so far,'' Gallen said.
''We've (Gallen and Bird) been known as the 'Bruise Brothers', but if we get knocked out we'll be the 'Snooze Brothers.'
''Let's hope that doesn't happen.''
There'll be a few NRL coaches hoping the same.
''He just said enjoy the experience and come back in one piece,'' Mason said of the last words of advice from Knights coach Wayne Bennett.
''He'll be blaming Flavs (opponent Troy Flavell) if I get knocked out.''
A popular villain across the Tasman, Mason has assumed the role of headline act with his heavyweight bout against 22-Test former All Blacks second-rower Flavell.
Of all the fighters taking to the ring on Saturday night, Mason - who has been training with three-time world champion Jeff Fenech - is seen as the one most likely to make a career as a pugilist.
His desire to box was one of the chief reasons he quit the Bulldogs in 2007, but he said he was taking a wait-and-see approach to any possible career change.
But following the lead of good friend Sonny Bill Williams and mixing boxing with footy wasn't on the cards.
''I don't know if I want to keep training this hard,'' Mason said of the possibility of turning his hand to boxing fulltime.
''I might think about it after (Saturday night), but I'm dedicated to the Knights for two more years.
''I don't think I'll be one of those blokes throwing in a couple of fights every year because I know how hard it is to play at the top of the NRL and to box at a high level - it's 24-7.''