Girls Aloud star Sarah Harding and her former boyfriend Theo De Vries could both face court charges after they were involved in a fight during the early hours of New Year's Day.
The altercation began in their hotel room during a holiday to Austria.
Sarah, 30, told police the Dutchman, a friend from rehab, attacked her after she decided to end their break early.
Theo says she was the one who started the fight and he was injured while trying to restrain her.
The 35-year-old sunglasses salesman has made no formal complaint.
But authorities say that while they questioned him it was clear he had also been injured.
The romantic skiing holiday went wrong, says Sarah, when Theo started drinking.
"We met in rehab and I was at a real low in my life. We got on really well and he was a completely different person when we were in rehab," she told the Sun of their romance.
"They do say it's frowned upon to get together with someone in rehab, but I thought it was a safer option because we could both stay clean together and sober.
"When we got to Austria he said we could have a couple of drinks. He suggested it.
"They say when one relapses, so does the other one and that's the danger of it.
"So yeah, I ended up having a few drinks with him and things got out of hand.
I felt I had really let myself down to be honest. I am really ashamed about that.
"After three days over there I had booked a flight to come home because we weren't getting on, making each other miserable.
"But my flight got cancelled when I got to Innsbruck. So I went back to the hotel and that's when it all kicked off."
Sarah recently spoke about her time in rehab in an exclusive interview with HELLO! magazine.