Richie McCaw knows how to beat the British and Irish Lions having done so twice in his esteemed New Zealand career.
The former All Blacks captain, who retired in 2015 with 148 international caps to his name, could give the current side a tip or two ahead of their two-Test series.
But, speaking exclusively to the Daily Mail, McCaw explains why Warren Gatland's men should give extra special care to four All Blacks.
"For a big man, he's got so much skill, so much presence and he doesn't take any nonsense. He's really good at the basics - catch and pass - under pressure to link the backs and the forwards. He's not just a big hitter, he's been a big asset for the All Blacks over the last year."
"Calm head on young shoulders. I first played him in 2011 and I thought: 'Bloody hell, this guy's all right.' Some guys really flash things and then go spare for a while, but he's always there or thereabouts. He'll be doing the ugly stuff at the tackle or the breakdown. He's a little bit like myself."
Sonny Bill Williams
"The guy's a bit of a freak. I used to play against him and as soon as I thought I had him covered, he suddenly pops the ball out of the tackle to find a guy in space. He's an amazing athlete who can do things others can't. He showed he's a match-winner when the Blues beat the Lions."
"There was a lot of talk about who would replace Dan Carter and Beauden has stepped up. You can't afford to give him any time or space because he makes things happen with a kick, pass or a break. You've got to cut off any ball if you're marking him. He could cause chaos with Sonny Bill."