Newcastle United owner and sportswear firm boss Mike Ashley is embroiled in a High Court fight relating to an alleged conversation in a pub.
Finance expert Jeffrey Blue says Mr Ashley - who runs Sports Direct - made a promise during a meeting in a London pub called the Horse & Groom more than two years ago.
Mr Blue says Mr Ashley promised to pay him £15million if he used his expertise to increase Sports Direct's share price to £8 a share. He says Mr Ashley paid only £1million.
Mr Ashley disputes his allegations and denies that an agreement of that nature was made.
A judge analysed pre-trial issues at a preliminary High Court hearing in London on Wednesday.
Mr Ashley was not at the hearing, but was represented by barrister Tony Singla.
Lawyers say any trial is likely to be staged in 2017.
Barrister Jeffrey Chapman QC, who represented Mr Blue, outlined some detail of the case to Mr Justice Phillips in a written document.
Mr Blue claimed that Mr Ashley conducted business discussions orally - including when "consuming alcohol", Mr Chapman told the judge.