Prosecutors, who plan to file a misdemeanor battery charge against the star have not been released to the public but's believed the plea could let the actor-director avoid jail time.
Gibson, 55, will plead guilty in court Friday afternoon in front of Judge Stephanie Sautner, on charges which stem from a dispute between Gibson and Grigorieva in January 2010.
Cops began their investigation into the domestic abuse allegations in July 2010 after Grigorieva accused Gibson of punching her and threatening her with a gun during an altercation at his home in Malibu.
She later released a series of racist and profanity-laced recordings of him
abusing her to the press, which seriously damaged his already tarnished reputation.
Gibson's attorney Blair Berk said in a written statement that the star had his kids in mind when he took the decision.
He said: "I know from almost 20 years as a criminal defense lawyer that sometimes justice can come for a client at too high a personal price.
"That is particularly so for Mel, whose right to due process can only be exercised in this case with an enormous media circus attached."