(CNN) Tom Brady may or may not have his eye on retirement, but he's certainly expanding his portfolio of extracurricular interests -- this time, putting his cash into pickleball.
Last month, the seven-time Super Bowl champion twice hinted that retirement was not too far away, saying he was "close to the end" of his NFL career.
Now, the 45-year-old quarterback, along with former world No.1 tennis player Kim Clijsters, has joined an ownership group which has bought an expansion team for the 2023 Major League Pickleball (MLP) season.
MLP founder Steve Kuhn said he was "thrilled" to add the stars to the league's list of strategic partners, adding they "are champions in their fields and will now be champions for Major League Pickleball."
Brady and Clijsters follow in the footsteps of other sports titans, including LeBron James and fellow NBA players Draymond Green and Kevin Love, who earlier this year were revealed to have joined a consortium which is buying an expansion franchise in MLP as the competition grows from 12 to 16 teams.
"We are thrilled to welcome them to our unrivaled roster of strategic partners, who are individually and collectively instrumental in helping us elevate professional pickleball, showcase the joy it brings to millions of people around the globe, and further our '40 by 30' campaign -- our mission to reach 40 million pickleball players by 2030," Kuhn added in a press release.
The basic aim of pickleball, like with other racket sports, is to hit the ball over the net and prevent an opponent from hitting it back.
It can be played in singles or doubles, inside or outside on a 20-foot by 44-foot court -- approximately the size of a badminton court -- and lasts until one side reaches 11 points, with a two-point cushion.
Pickleball's popularity has skyrocketed in North America, partly driven by the Covid-19 pandemic as it offers a safe, socially distanced form of exercise.
It had originally found a solid base among retirement communities where it was beloved for its sociable aspect, moderate exercise, and for simply being fun.
Between 2018 and 2021, however, USA Pickleball membership nearly doubled and the organization estimates that 4.8 million Americans now play the sport.
The New Yorker even asked if pickleball can save America, Ellen DeGeneres ran a segment about her "obsession" with it on her eponymous TV show, Vanity Fair wondered how it had won everyone over, and the Kardashians played it on their own reality show.
The financial terms of Brady's Clijsters' investment were not disclosed.