World heavyweight champion Lennox Lewis is filing a legal action to prevent Mike Tyson fighting Ray Mercer on January 19th.
Lawyers representing Lewis have applied for an injunction in Manhattan Federal Court that would stop the Tyson-Mercer fight.
Lewis has also requested the WBC remove Tyson from the mandatory challenger's position if he does fight, stating that the clash could hurt Lewis financially if the contest goes ahead.
Tyson replied in a statement saying that he was "outraged by Lennox's attempt to interfere with my career". He said: "I stepped aside as the WBC challenger in November to allow the rematch with [Hasim] Rahman".
Lewis, who regained the WBC-IBF heavyweight titles by knocking out Rahman last month, is supposed to face Tyson in April, although that fight is not yet signed.
A Lewis-Tyson is expected to be worth at least $20 million to each fighter.