Former world number one Dustin Johnson is set to play in the LIV Golf Invitational Series ©Getty Images

Two-time major winner Dustin Johnson is the highest-ranked player to agree to join the Saudi-backed breakaway golf league despite previously pledging his commitment to the PGA Tour.

The American former world number one headlines the initial 42-strong field to play in the opening leg of the controversial LIV Golf Invitational Series.

The world number 13 will be joined by fellow major winners Sergio Garcia of Spain, Martin Kaymer of Germany, Graeme McDowell of Northern Ireland and South Africans Louis Oosthuizen and Charl Schwartzel.

A total of 26 of the world’s top 150 golfers have been confirmed for the event which is expected to feature 48 players.

The first leg of the breakaway tour is scheduled to be held at the Centurion Club in Hertfordshire on the outskirts of English capital London on June 9.

Johnson stressed in February that he was "fully committed" to the PGA Tour but has performed a U-turn.

He is now at risk of being banned from the PGA Tour which has denied permission for its players to take part in this month’s LIV Golf Invitational Series tournament.

His agent David Winkle told Golf Channel that the opportunity to play in the LIV Golf Invitational Series proved too big to turn down.

Sergio Garcia is among 42 players that have been confirmed for the opening event of the LIV Golf Invitational Series ©Getty Images
Sergio Garcia is among 42 players that have been confirmed for the opening event of the LIV Golf Invitational Series ©Getty Images

"Dustin's been contemplating this for the past two years and decided it was in his and his family's best interest to pursue it," said Winkle.

"He's never had any issue with the PGA Tour and is grateful for all it's given him but in the end felt this was too compelling to pass up."

Next week’s opening event is one of seven tournaments that are set to boast a total purse of $25 million (£19 million/€22.6 million), with $20 million (£15.2 million/€18.1 million) in individual prizes.

Australian two-time major champion Greg Norman is chief executive of LIV Golf Enterprises, the company behind the breakaway and majority owned by the Public Investment Fund which operates on behalf of the Saudi Government.

The LIV Golf Invitational Series is viewed by critics as being part of Saudi Arabia’s "sportswashing" of the country's human rights records - an accusation Norman denies.

"Free agency has finally come to golf," said Norman.

"This is an opportunity to start a movement that will change the course of history by bringing new and open competition to the sport we all love.

"The desire shown by the players to participate in LIV Golf demonstrates their emphatic belief in our model and confidence in what we're building for the future."

PGA Tour commissioner Jay Monahan is also chair of International Golf Federation (IGF) Board, but so far the IGF has said it is "premature" for it to take a stance on the LIV tournaments.