Ben Roberts-Smith's ex-girlfriend has told a Sydney court the war veteran punched her in the face in a Canberra hotel room and told her to lie about the injury to her husband.
Mr Roberts-Smith is suing The Sydney Morning Herald, The Age and The Canberra Times newspapers over a series of articles published in 2018.
The Victoria Cross recipient claims he was defamed by false allegations in those stories of an act of domestic violence against the woman, bullying of his Special Air Service Regiment (SAS) colleagues and unlawful killings in Afghanistan.
Codenamed Person 17, the woman today told the Federal Court the two met at a charity event in October 2017 before they flirted and spoke about both having marital problems.
Person 17 said she told the veteran she thought she was falling in love with him and he replied: "You don't want to fall in love with me, I'm not the greatest guy."
The court heard they saw each other roughly every 10 days in what she described as a "fast moving" and "all-consuming" relationship.
She said by late 2017, they'd spoken about long-term plans to leave their respective marriages and move to the United States.
In March the following year, she said she fell pregnant and knew it was Mr Roberts-Smith's child, and the pair spoke about a termination before she miscarried.
The court has previously heard Mr Roberts-Smith paid a private detective to follow Person 17 to an abortion clinic because he suspected he was being "manipulated".
Person 17 told the court the veteran made her take two pregnancy tests in front of him in a Brisbane hotel, at which point she tearfully told him about the miscarriage.
She recalled at a Parliament House function in Canberra on March 28, Mr Roberts-Smith was "looking at me from the stage and subtly shaking his head", which she assumed related to her drinking and speaking to men at her table.
Person 17 said she was "quite drunk" by the time she left and fell down some stairs, causing a bruise to her thigh.
At their Canberra hotel room, she said Mr Roberts-Smith became "really angry".
"He was sort of up in my face just inside the doorway and he was shaking me by the shoulders and he said: 'What the f*** have you done.'" Person 17 said.
"He said: 'What have you done… you were all over the other men at dinner, they're all going to know we're having an affair, I should have just left you there, you made a big scene as we were leaving.'
"He said: 'I let you into my world and I trusted you and you just treated it like a high school formal.'"
Person 17 told the judge she repeatedly apologised.
"I said to him: 'My head's hurting... let's just go to bed, let's forget about it,'" the witness said.
"He'd been pacing around in the lounge area and was getting angry with me.
"He punched me with his right fist on the left side of my face and eye."
Person 17 said she fell backwards towards a bed.
"I just lay there still, I didn't know what he was going to do next," she told the court.
Last year, Mr Roberts-Smith denied hitting the woman and described domestic violence as "deplorable", "reprehensible" and "a disgusting act of cowardice".
Today, the court heard after the two flew back to Brisbane the following day, Mr Roberts-Smith asked her if she remembered what happened in the hotel.
"I said no, he said something like: 'Good girl, you hurt yourself when you fell over.'"
Asked why she didn't admit that she remembered, Person 17 replied: "I was afraid of what he would do if I didn't say that."
The trial, before Justice Anthony Besanko, continues on Wednesday.
