Woolf, who finished the NRL season as caretaker boss of Newcastle Knights, will become the eighth Australian to coach the club since the arrival of summer rugby in 1996.

He follows in the footsteps of Shaun McRae, Ian Millward, Daniel Anderson, Mick Potter, Royce Simmons, Nathan Brown and Holbrook, with only British duo Ellery Hanley and Keiron Cunningham breaking the sequence in that 23-year period.

St Helens chairman Eamonn McManus said: "We consider that Kristian is ideally qualified and placed to build upon the current success of the team and the club.

"He has the experience and expertise to bring the best out of our existing squad and to improve it further.

"We are very confident that the Saints will seriously compete for honours under his tenure and that we will continue to play attractive and exciting rugby league."

Saints are also continuing a growing trend of Super League clubs seeking out assistant coaches from the NRL.

Trent Robinson and Michael Maguire achieved their mark in Super League with Catalans Dragons and Wigan respectively before landing top jobs in the NRL and Holbrook has followed suit.

Woolf said: "I'm excited and privileged to be joining St Helens as head coach. It's something I have always wanted to do and it's a great opportunity for me.

"St Helens is a club with an amazing history and I'm confident we can achieve great things together."

Woolf has been assistant coach at Brisbane, North Queensland Cowboys and Newcastle but is best known for his success with Tonga.

In his five years at the helm, Woolf improved the nation's world ranking from 14th to fourth and guided them to the semi-finals of the 2017 World Cup, defeating New Zealand and pushing England all the way in the semi-finals.

His tenure was ended by the Tonga board last Thursday and prompted a backlash from players loyal to their former coach which puts a question mark over Great Britain's scheduled opening tour match against the Pacific nation in November.