When news first broke that Demi Lovato had entered a treatment facility to deal with personal issues, it was reported that an altercation between Demi and a female dancer had been a factor in the Disney star's decision to seek help.

Now, dancer Alex Welch — who was on the road with Lovato and the Jonas Brothers — is speaking up about the incident, which reportedly took place in late October, just before Lovato announced she was leaving the JoBros' tour.

"To this day, I haven't gotten an apology. I've heard nothing," Welch told People magazine on Monday (December 6). "That's sad if you think that person is your friend."

According to reports, Lovato was angry when she found out someone on the tour had told tour managers about her partying. Welch said the teen star "pulled the dancers in a room and threatened: 'If I find out who told on me, ' " adding that she was clueless about what Lovato was referring to.

"I felt, honestly, I didn't say anything and didn't think twice about it," Welch recalled. "We were on the plane with the Jonases having this awesome time, and I didn't get a call or text from Demi or a 'hey, you got a problem with me,' nothing. And she walks up and punches me and, literally, walked away and got in her seat," she continued. "No one should walk up and do that and brush it over, it's not right."

TMZ posted photos of Welch with what looked like a black eye.

The dancer said she's looking at her legal options now. "We have contacted the Lovato camp and we are waiting for a response. If we don't hear back, we will pursue litigation."

A rep for Demi confirmed that, saying, "We are in the process of engaging with Alex's lawyer and hope to resolve this as quickly as possible." The rep added, "Demi feels awful about what happened. Right now, she is 100 percent committed to her treatment."

What do you think of Alex Welch's side of the story? Tell us in the comments.