By Breaking Celebrity News Staff

Maksim Chmerkovskiy isn't backing down from his razor sharp jab to Len Goodman, two days after he told Dancing with the Stars' 67-year-old head judge, “Maybe it's time to get out" of the ballroom business.

"I have nothing to apologize for to Len," the Russian pro dancer, 31, told Good Morning America on Wednesday. "The last time I apologized was to my grandma when she was dying of cancer."

As we previously reported, after Chmerkovskiy and his celebrity partner Hope Solo danced the rumba to the musical Rent, Goodman told Solo she'd just finished her "worst dance of the whole season" -- a comment which caused the crowd to jeer (encour