Sam Allardyce is suing Blackburn Rovers manager Steve Kean over comments the Scot made about his predecessor at Ewood Park.
A video emerged on Monday night showing a drunk Kean label Allardyce a "f*****g crook" on Rovers' 2011 Far East tour, and Allardyce, currently managing West Ham United, has instructed his lawyers to initiate proceedings against his successor.
Kean made the comments six months after Allardyce was suddenly dismissed by the club's owners the Venky's in December 2010.
The 44-year-old was due to meet the club's hierarchy for talks in Pune today, after the club were relegated from the Premier League.
Kean was Allardyce's assistant during his two-year reign at Ewood Park, before he was promoted to manager after the 57-year-old was sacked.
After Rovers' final home match of the 2010/11 season against United, Kean was charged by police with drink driving.
In August 2011 the 44-year-old was convicted at Macclesfield Magistrates' Court. The Court rejected his defence that his drinks had been spiked following the game and he was banned from driving for 18 months and fined £1,800.
Rovers were relegated last week after a 1-0 home defeat to Wigan Athletic, ending their 11-season stay in the Premier League.
Supporters have protested against Kean and the Venky's throughout the campaign, angered by perceived mismanagement at boardroom and team level.
Vitriol towards the Scot has risen to such a degree he has had to be accompanied by a bodyguard in Blackburn town.
Last week a letter was leaked written by the club's deputy chief executive Paul Hunt. Penned in December, Hunt outlined a 10-point plan imploring owner Mrs Desai to dismiss Kean and make an effort to build bridges with disenchanted supporters.
Shortly after the letter was made public, Hunt was sacked from his role while Kean remains in charge of the 1995 Premiership champions.