Phil Mickelson (right) and Greg Norman (left), who is fronting the controversial Saudi Arabia-backed LIV Golf Invitational SeriesSix-time major champion Phil Mickelson will play at this week's opening event of the LIV Golf Invitational Series after a four-month break from the game.
Mickelson has not played since controversial comments about the Saudi-funded breakaway series were published by his biographer in February.
The American has now been added to the field at Centurion Club in St Albans.
The 51-year-old had sought a release from the PGA Tour to play in the first event of the Greg Norman-led series.
However the PGA Tour has said players taking part in the event could face sanctions.
In a statement on Twitter, Mickelson said taking time away from the sport has been "humbling".
Mickelson lost multiple sponsors and saw his reputation tarnished after he criticised the Saudi regime, yet sought to use involvement with the Saudi Arabia-backed golf super league to gain leverage over the PGA Tour.
He subsequently missed the Masters for the first time in 28 years as well as last month's US PGA Championship, where he was defending champion.
"First and foremost, I want to again apologise to the many people I offended and hurt with my comments a few months ago," he saidexternal-link.
"I have made mistakes in my career in some of the things I have said and done. Taking time away and self-reflecting has been very humbling."
Having missed the last two majors, Mickleson says he intends to continue playing in the biggest tournaments.
He added: "I am thrilled to begin with LIV golf and I appreciate everyone involved. I also intend to play the majors.
"I fully realise and respect some may disagree with this decision and have strong opinions and I empathise with that.
"I am ready to come back to play the game I love but after 32 years this new path is a fresh start, one that is exciting for me at this stage of my career and is clearly transformative, not just for myself, but ideally for the game and my peers."
The LIV Golf International Series is regarded as the first incarnation of the proposed breakaway Super League.
Mickelson has reportedlyexternal-link accepted a package worth £24m to compete in the eight-tournament series. He is joined by players such as two-time major winner Dustin Johnson, England's former world number one Lee Westwood, Ian Poulter and Spaniard Sergio Garcia.
Norman has shelved plans to run the series as a league format, instead each event will run as an invitational tournament until 2024.
"Phil Mickelson is unequivocally one of the greatest golfers of this generation," said Norman. "His contributions to the sport and connection to fans around the globe cannot be overstated and we are grateful to have him.
"He strengthens an exciting field for London where we're proud to launch a new era for golf."
This initial $255m (£202m) invitational series will feature six more regular season tournaments in 2022 - four in the United States, one in Thailand and one in Saudi Arabia - each having the same $25m (£20m) prize fund, meaning every leg of the series is more lucrative than the richest tournament on the PGA Tour.
The events will feature a team and individual competition, with 12 captains selecting three players in a draft-style format. Each day, the teams of four will tee off at the same time on different holes in what is termed a 'shotgun start'.
Each event's individual winner will take home $4m - by way of comparison, the PGA Tour's flagship event, the Players Championship, earned Cam Smith $3.6m for his victory in March, while Collin Morikawa won $2m for his Open Championship victory in 2021.
Analysis
Iain Carter, BBC golf correspondent
Mickelson's comments, heavily critical of Saudi Arabia and the PGA Tour, were made public in February and spectacularly derailed the LIV Golf project.
The then reigning US PGA Champion was the intended face of a new Formula One style golf super league. Instead, he disappeared from public life, admitting he needed to take steps to become a better person.
This was regarded as a huge downfall for one of golf's most popular figures. But despite graphically branding the Saudis as "scary" he is making his return at the first of their events. He is likely to be receiving big appearance money that will run into millions of dollars.
Mickelson says he will continue to play majors but it is significant that he makes no mention of the PGA Tour in a future that now involves, as originally intended, being the LIV project's most illustrious poster boy.
