NSW five-eighth Cody Walker has revealed he quit alcohol this season in a bid to discover the career-best form that has catapulted him into a State of Origin debut.

With his focus squarely on game one of the series in Brisbane next Wednesday, the 29-year-old South Sydney playmaker was a notable absentee from the Blues' bonding session on Tuesday night, having made a decision in round two to give up the booze.

Sacrifice: Cody Walker is intent on getting the best out of himself as he prepares for a State of Origin debut. Credit:Cole Bennett

"My manager brought it up and I said, 'yeah I agree with you'," Walker told the Herald. "A couple of the boys were going 'what are you doing that for?' I've just said, 'I can't control myself when I have one or two', so why have one or two?"

Walker said his partner Nellie Bell "laughed" when he told her of the decision.