Reese Witherspoon will be called to testify about Ryan Phillippe in the lawsuit brought against him by his ex-girlfriend.

Elsie Hewitt is suing the 44-year-old actor - who she dated from April to July 2018 - over an alleged incident at his home two years ago, where she claims he was violent towards her during an argument.

The Guess model alleges she went to Ryan's house with a friend to pack up her things after a party, which the actor had left earlier after ''being ignored'' by her, when a physical altercation ensued.

And she has put Oscar winner Reese, 43, - who has 19-year-old daughter Ava and 15-year-old son Deacon with Ryan - to testify against the actor, according to The Blast.

The trial will begin on October 15 and Ryan previously attempted to keep Reese - who he divorced in 2007 - from being called to testify, with his lawyers arguing in court filings that she is not relevant to the case.

They stated in a court filing: ''Although divorced, they maintain a pleasant relationship with each other and their child. The nature of their marriage and its termination, as well as their ongoing relationship could only be used in this trial for improper purposes.''

Earlier this year, Ryan also lost a bid to have his former fiancée kept out of the lawsuit.

The 'Shooter' actor had applied for a protective order prohibiting Paulina Slagter from being deposed by lawyers acting on behalf of Hewitt but the judge is allowing her to be called to testify.

The judge ruled: ''Testimony by Slagter that contradicts or undermines statements Defendant made about his own character or his knowledge of other domestic violence investigations would be relevant to this action.

''Accordingly, the motion for protective order is denied.''

Both Ryan - who denies the claims - and Elsie had asked for one another to be sanctioned but the judge denied both requests.

Ryan previously launched a lawsuit of his own against Elsie, slamming her version of events as being completely ''fabricated'', as he has claimed she broke into his home in a bid to ''extort money''.

Ryan also claimed that Elsie was ''extremely intoxicated'' during the encounter.

The star said he felt ''sickened'' by the ''false'' domestic violence accusations made against him because he grew up around women and was an advocate for women's rights.