PFA chief Gordon Taylor 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.
Manchester United star 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.