Derek Hough on sister Julianne's blackface: 'It wasn't her brightest moment'

(UPI) -- Julianne Hough has already apologized for dressing in blackface as part of an Orange Is The New Black costume.

Now, her brother Derek Hough has commented on the controversy. The Dancing With The Stars pro said that his sister is "mortified" over the backlash she has incurred over her costume, which she wore to a Halloween party in Hollywood on Friday.

She dressed as Orange character Crazy Eyes, who is portrayed by Uzo Aduba in the hit Netflix show. Derek Hough said she did not mean any harm with the costume.

"She's my little baby sister and she's the sweetest thing ever," said the older Hough, who also attended the Halloween party.

"She is just beyond beside herself. She's so apologetic. She's so so sorry.”

"Obviously, it wasn't her brightest moment in her life, but hopefully we can move on," he said.