TVGuide.com quoted the bombshell admission from the U.S. Olympic soccer champ's book, "Solo: A Memoir of Hope."
"He was often nasty, swearing at me and being harshly critical. He manhandled me in rehearsals from the start, pushing me, whacking my stomach, bending my arms roughly. One day, Maks was trying to put me in a certain position and hit my stomach so hard with his open palm that I had a red hand-print there for the rest of the day," Solo wrote.
Another time, Solo said, Chmerkovskiy slapped her across the face so hard her ear rang afterward.
"He was extremely apologetic. I didn't care," TVGuide.com said she wrote. "My ear was ringing as I walked out, shaking. I had just been hit, and I had been worried about how I would come off looking on television."
Chmerkovskiy said via Twitter Thursday: "Always hated hypocrites and liars ... but when someone is both AND an opportunist, I just feel bad for them. Can't win at someone's expense."
TVGuide.com said Chmerkovskiy's publicist and ABC declined to comment on Solo's allegations.