Timothy Dalton will testify on behalf of Oksana Grigorieva against Mel Gibson.
The Russian-born singer reportedly revealed to the former 'James Bond' star - the father of her 14-year-old son Alexander - that the 'Braveheart' star had hit her when he questioned her about bruises on her face.
In a letter to Eric George - the son of California's former chief justice - on June 3, 2010, Oksana stated that both 'Licence to Kill' star Timothy and her facialist Mady Shany are willing to testify on her behalf.
According to website RadarOnline.com, she wrote: "Tim saw a bruise on my left eye as well as Mady. Both will testify. Facts and witnesses."
While Mel has not yet been charged with assault for the alleged attack last year, prosecutors are said to have a "strong case" to support filing criminal charges against the 55-year-old star and Timothy's testimony could help.
It is believed the charge is likely to be violence or corporal injury involving a former cohabitant, which can be prosecuted as either a felony or misdemeanour.
A source has previously said: "The District Attorney (DA) has a very strong case, there is a lot of information that the public and Mel Gibson are unaware that the DA has."
Oksana, 40, has claimed Mel punched her in the head at his Malibu home, which knocked two veneers out from her upper front teeth while she held their daughter Lucia, now 15 months.
While Mel has confessed in a written declaration that he slapped her during an argument because she was hysterical, he denies hitting her. He was however caught on audio tape calling Oksana a "fickle ****" and telling her she should go "f**k" Timothy.