Last hurrah for Sonny Bill show?

The Sonny Bill Williams Rugby Union roadshow could come to an abrupt end in Hamilton on Friday.

Williams, who will head to Japan for a year before embarking on a second Rugby League career, will turn out for the Chiefs against the Crusaders in the Super Rugby semifinal.

If the Chiefs win, he will have another outing for them - either against the Stormers in Cape Town or the Sharks in Hamilton.

Defeat for the New Zealand conference winners, the Chiefs, will mean Saturday is Williams' last Rugby Union outing in New Zealand for many years ... perhaps forever.

However, he is taking the pressure in his stride.

"I don't want to get too emotionally attached to it, because it could be my last week here, but I'm just trying to turn all those emotions into motivation," Williams said told Fairfax NZ News.

"I want to come in, do all my work and try and build like I haven't done it before - try and tick all those boxes.

"And then hopefully run out there on Friday night fizzing and just do my role really well."

Williams is no stranger to big matches, having played for the Crusaders last season, experienced the All Blacks' World Cup-winning campaign and been through some big play-off games on the way to winning the NRL title with the Canterbury Bulldogs in 2004 as a young rookie. He knows what approach works best in these situations.

"You've still got to do what you do, keep it simple and nail everything you do during the week so you're confident," he told Fairfax NZ News.

"That's probably what I will do. Just nail everything that I usually do and go into the game knowing I've done everything I can, then just play footy and back myself."

Williams predicted the semifinal would be a step up from any other game the Chiefs had played all year, including the hugely intense last clash between the two sides at Waikato Stadium 2 weeks ago.

"You've just got to be at your best and in those times when you're in that dark place that's when you use it as well to try and pull something out, keep pushing hard, keep getting up off the deck and making that extra tackle - just things like that," he said.