Mickelson, who won his sixth major title Sunday to became the oldest major champion at age 50, will be part of a July 6 match with Tampa Bay Buccaneers quarterback Tom Brady. They will take on DeChambeau and Green Bay Packers quarterback Aaron Rodgers at The Reserve at Moonlight Basin in Big Sky, Montana.
TNT will televise the event (5 p.m. ET), as Turner Sports and WarnerMedia are partnering with event organizers Sportfive and Excel Sports Management.
Mickelson foreshadowed another match on Sunday night after his victory when he complimented Brady for inspiring him during an ESPN interview and then later in tweeting at Brady, who had congratulated him.
"We have some unfinished business," Mickelson responded to Brady in his tweet. "Let's get another match and find another pair to give a beat down.''
Brady continued to taunt Rodgers and DeChambeau on social media Wednesday, with DeChambeau entering the fray later in the afternoon.
"Two old guys against the young bucks @PhilMickelson," Brady tweeted. "@b_dechambeau better get used to laying up because we know @AaronRodgers12 isn't going for it [laughing emoji]"
Responded Mickelson: "True Dat partner!"
Said DeChambeau on Instagram: "Can't wait to unleash the beast in Big Sky. Get your popcorn ready, this is going to be epic."
The tournament is being called Capital One's The Match and follows others that Mickelson has been involved in, including one last year in which he and Brady lost to Tiger Woods and Peyton Manning in a charity match for COVID-19 relief.
The DeChambeau-Rodgers opened as the -180 favorite at Caesars Sportsbook by William Hill, with the Brady-Mickelson pairing at +160.
The original match in 2018 featured Mickelson and Woods in a head-to-head encounter, with Mickelson claiming the $9 million prize for winning.
The format will be modified alternate shot, meaning they likely will have each player hit a drive, pick the best one and alternate until the hole is completed.
There will be a charitable aspect that includes Feeding America and other charities.