The pop singer, 27, was allegedly injured in a fight outside the Hollywood Roosevelt Hotel in the early hours on Sunday. Jenner, her boyfriend, was also injured, apparently when he tried to intervene.
Both of them later Tweeted about the incident.
“I got attacked by 5 people last night out of nowhere. Not cool. My face is f––ed,” Lavigne wrote. “As in black eye, bloody nose, hair ripped out, scratches, bruises and cuts. So not ok to be abusive to others. Violence is NEVER the answer.”
Jenner, 28, a former star of MTV’s The Hills, was seen with a gash on his head in video stills from the scene. “Interesting Saturday night,” he tweeted. “Just got of the hospital with a new scar on my face. Charges/chargers!!!”
It was unclear who the assailants were, or whether police had any leads. An LAPD spokesman had no confirmation of the alleged fight.
The night had started promisingly for the couple, with Jenner tweeting a picture of them together, along with the note: “Having the best night with the love of my life @AvrilLavigne so happy right now!!”