Julianne Hough made a surprise return to "Dancing with the Stars" on last week's results show. Now she is back in the rehearsal studio getting ready for tonight's competition -- and ET is with the two-time champ and her partner Cody Linley.

"I was nervous because I've never had surgery. I've never really had anything internally wrong with me," she tells ET.

Julianne's health crisis was the toughest thing the country singer says she has ever faced, and she explains her decision to have the surgery when she did.

"I asked the doctor if I could do the surgery after the competition was completely over so that I could be there for Cody. They said, 'Julianne, I think you should do it now. You've been feeling these pains for quite some years.' But I never went into the doctor," she admits.

Julianne had her appendix removed, as well as some cysts, because she was thinking of her future family and the fact that she has always wanted to have children. So does that mean things are heating up with her boyfriend, country singer Chuck Wicks?

"He was, obviously, there with me when I had my surgery. He was there every single day like little Nurse Betty," she says.

Tonight, Cody and Julianne will need to put their best foot forward when they dance two Latin numbers -- the salsa and the paso doble -- in order to make it to the finals.

But first, Cody tells us about a surprise visit to the ballroom by his "Hannah Montana" co-star.

"Miley Cyrus will be coming to support us at 'Dancing with the Stars' because she's a big supporter," he reveals.

The "Dancing with the Stars" semi-finals begin tonight at 8 p.m. on ABC.