DeChambeau bulked up during the Covid pandemic lockdown to help him hit the ball further and then won the 2020 US OpenBryson DeChambeau has become the most significant player to turn his back on the PGA Tour and join the new Saudi-funded LIV Golf Invitational series.
The American, 28, won the 2020 US Open and is in the prime of his career.
He has been unveiled the day after the PGA Tour said it was suspending any members who joined the rival circuit.
DeChambeau's first appearance will be in the second of the $250m eight-event series, which starts on 30 June in Portland, Oregon.
LIV Golf chief executive Greg Norman said DeChambeau was "an exciting addition" because he is "passionate and innovative in his approach and committed to pushing the boundaries".
"He's not afraid to think outside the box and supports our mission of doing things differently to grow our game."
DeChambeau, who turned professional in 2016 and officially joined the PGA Tour in 2017, is the eighth major champion to join the fledgling series.
He has spent much of the past two years in the top 10 in the world rankings but is currently 28th, having slipped down after injuring himself at the Saudi International in February.
He took a "huge risk" to return early from that injury to play in the Masters, the year's opening major. But after missing the cut at Augusta National, he underwent surgery on his left hand, which led to him missing the US PGA Championship last month.
DeChambeau then missed the cut at last week's Memorial Tournament, which looks set to be his last on the PGA Tour, given the statement sent to all its members by commissioner Jay Monahan on Thursday.
Monahan wrote: "In accordance with the PGA Tour's tournament regulations, the players competing this week without releases are suspended or otherwise no longer eligible to participate in PGA Tour tournament play, including the Presidents Cup.
"The same fate holds true for any other players who participate in future Saudi Golf League events in violation of our regulations.
"These players have made their choice for their own financial-based reasons.
"But they can't demand the same PGA Tour membership benefits, considerations, opportunities and platform as you. That expectation disrespects you, our fans and our partners."
The PGA Tour refused to allow requests for waivers to play in the first LIV Golf event, which is currently being played at Centurion Club, near London.
Six-time major champion Phil Mickelson and former world number one Dustin Johnson among the biggest names in the 48-man field.
Johnson resigned his membership of the PGA Tour on Tuesday, while lifetime member Mickelson hoped to hang on to his.
England's Ian Poulter has vowed to fight the decision, while Lee Westwood, Sergio Garcia and Graeme McDowell all confirmed they had resigned from the dominant American-based Tour before Monahan's memo was sent out.
The European-based DP World Tour continues to remain quiet on the situation. It has a 'strategic alliance' with the PGA Tour, which McDowell fears may force their hand.
On Thursday, the Northern Irishman, winner of the 2010 US Open, said: "I hope Keith [Pelley, DP World Tour chief] doesn't follow suit but they may have to."
More to follow.
