A cage fighting champion from County Durham has admitted charges of tax evasion and tax credit fraud.
Ian Freeman, who is professionally known as "the Machine", is believed to have stopped paying tax in 1997 when he left his job as a security guard.
Appearing at Durham Crown Court, the 42-year-old from Stanley, pleaded guilty to tax evasion of over £21,000.
He and his wife Angela, 34, also jointly admitted tax credit fraud more than £13,000.
The pair will be sentenced on 3 March.
Freeman ran his own fight promotions firm and made television appearances but failed to declare his earnings of around £30,000 a year, the hearing heard.
The couple also bought a new £18,000 car and a £27,000 boat before they were caught.
HM Revenue & Customs North East head of investigation, Peter Hollier, said: "Mr Freeman's blatant disregard for the tax system is beyond belief."