Adam Taylor/ABC

Former dance pro and two-time winner Julianne Hough returned to "Dancing With the Stars" Monday night and slammed her former competitive partner Mark Ballas for hogging the spotlight.

Following a side-by-side foxtrot by Ballas and his star partner Christina Milian, Hough - who was sitting in for head judge Len Goodman - said to Milian, "I really wanted to see you shine. I danced with Mark. You have to stand in front to make sure you're seen."

Ouch.

"She put a little sting on me, but that's okay," Ballas later told Entertainment Weekly. "That's how she felt. It is what it is."

"We take the high road," Milian said, jumping in. "As long as we know that we did a fantastic job, that makes me happy."

Watch Julianne Hough Becomes a Guest Judge

Hough, who left the show after season eight to pursue a singing and acting career, had warned fans on Twitter the week before that the "angel with devil horns" was coming back.

Ballas was prepared, telling ABC last week, "She's an angel, but she definitely has devil horns."

In general, though, Hough made good on her promise to be nice to the celebrities and offer them constructive criticism.

"I know how it is to be on the floor," Hough told host Tom Bergeron last week, adding that the No. 4 scoring paddle might just disappear. "I know what it takes to put all the effort and the time in each week."

Valerie Harper 'Not Sad' About 'Dancing With the Stars' Loss

Hough kept the praise and the scores high, even at the risk of appearing biased toward her brother Derek Hough.

"I was hoping something would go terribly wrong, so I wouldn't get in trouble," Julianne said after her brother's performance with star partner Amber Riley.

Later, Derek Hough told E! Online that his sister was just being honest and if he had done something wrong, "she would have taken much pleasure" in telling him so.

Julianne Hough seemed especially impressed by Brant Daughterty shirtless Salsa.

"Wow, um, that was awesome… when you took off the shirt," Hough told the "Pretty Little Liars" star, while reminding him, "I'm single now."