David Beckham and Mark Wahlberg, erstwhile friends and neighbors, have started a bitter feud, a new report claimed.

David has kicked the “Transformers” actor below the belt with a multimillion dollar lawsuit, severing their collaboration in the F45 Training fitness organization. The husband of Victoria Beckham, and Mark first met when the English soccer legend traveled to America to play for the Los Angeles Galaxy in 2007.

The English former professional footballer even lived in Mark's Beverly Hills neighborhood before he decided to serve as global ambassador for the brand, which is partially owned by his best friend.

David and Mark’s relationship has strained after the father of Brooklyn Beckham claimed that his stock shares were withheld until the price plummeted, which allegedly costed David more or less $11 million.

Initially, the ex-athlete sued for more than $20 million in 2022 together with golfer Greg Norman. However, a judge ordered David and Greg to file separate claims.

Mark and his co-defendants, fitness franchise entrepreneurs Adam Gilchrist and Rob Deutsch, feel the allegations of "fraudulent conduct" are unfounded and have asked the judge to dismiss the complaint.

“David and Mark and their wives were once as thick as thieves. But now David is actually calling Mark a thief,” an unnamed source told The National Enquirer.

For starters, court records divulged F45 entered into a promotional arrangement with David Beckham through his company DB Ventures Limited in 2020. In the years that followed, David argues, F45 failed to keep at least two promises: transferring roughly one million shares of stock in a timely way and issuing $5 million in extra shares. He claimed that the delay in transferring the initial shares cost him $9.3 million, as the stock price dropped.

The New York Times reported that David filed a lawsuit in May 2023, saying he is entitled to more than $14 million in damages from F45, not including interest. F45 is a fitness brand founded in Australia in 2013.

The company's network of franchisee exercise studios provides 45-minute bootcamp-style workouts overseen by in-studio trainers and electronic displays. According to the company's website, it has more than 2,000 studios across 50 countries.

According to the lawsuit, Mark bought a 36% share in the company through his investment organization in 2019. He is also on the board of F45. He frequently appears in promotional videos for the company, including one posted on the gym's Instagram account just this week.

Business Times has reached out to David Beckham and Mark Wahlberg for comments.