Mel Gibson's ex-girlfriend Oksana Grigorieva has claimed that she has a witness to prove that the actor has attacked her.

Grigorieva - who has a nine-month-old daughter Lucia with the actor - has accused the 54-year-old actor of pulling a handgun on her following an explosive row, in which he is believed to have broken her two front teeth and threatened her with a bat.

Sources say the witnesses have not come forward yet but they will tell the Los Angeles County Sheriff's Department they saw Mel punch Oksana on January 6 during the row at her home, according to gossip website TMZ.

It is believed one of the witnesses is someone who works with the 40-year-old Russian singer on her music, reports Contactmusic.

It has also been claimed at least one of the third party witnesses saw Gibson pull the gun on Grigorieva after he allegedly punched her. (ANI)