Gordon Taylor, chief executive of the Professional Footballers' Association, will give evidence in a £4.3 million lawsuit against Wayne Rooney today.
The former Blackburn Rovers player is listed as a witness in the case involving football agent Paul Stretford, who represented Rooney for six years.
Football agent Mel Stein, who used to manage Paul Gascoigne, will also give evidence at the hearing at Manchester Mercantile Court.
Rooney, 24, is being sued by his former sports management firm Proactive over unpaid commissions for a contract his parents signed when he was 17.
The Manchester United and England striker was signed up by Stretford, founder of the firm, as he burst onto the football scene with his home-town club Everton.
He brokered multimillion-pound sponsorship deals for Rooney and his wife, Coleen, stipulating a 20% commission rate for Proactive.
But when he left in acrimony in October 2008, no further commission payments were paid to the company.
Ian Mill QC, representing Proactive, told the court last week that Mr Stein will give evidence as their expert witness.
Mr Mill said the football agent will explain that for a player of Rooney's star quality to pay 20% in commission to a new firm of agents amounts to "unheard of" generosity in football.
Proactive's lawyers claim they are still due the commission payments - now amounting to a minimum of £4.3 million.
Rooney gave evidence on Friday, insisting he trusted Stretford - who was convicted of misconduct charges and banned as an agent - and was grateful for his help and management.Reuse content