The statuesque actress stunned in a sexy pink-and-black Versace gown featuring a thigh-high slit, and paired it with gorgeous black T-strap pumps. Her elegant updo and a diamond bracelet completed the high fashion look.
ET spoke with the Australian star at the event -- where she was fittingly honored with the Style Icon Award -- and she revealed her favorite red carpet looks of all time.
"I think I like the Dior... you know, the chartreuse that I wore," she tells ET's Nischelle Turner, referring to the iconic brightly-colored John Galliano for Christian Dior satin gown she donned at the Oscars in 1997.
"There was another beautiful gold Dior that no one comments on but was probably one of my favorites," she adds, also shouting out her bold look at the Oscars in 2000. "And I got to wear, like, the most beautiful 24-carat gold antique gloves that I still own -- fingerless gloves. There's just different things. I mean, so much of it for me is the combination of jewelry and dresses and the way it's all put together."
Kidman, 49, says her sense of style comes from her mother, who actually made her clothes growing up.
"I think because I grew up with a mother who could sew, she would make all my clothes for me ever since I was little," she reveals. "So I was able to think things up and tear stuff out of magazines when I got to be a teenager, and she would make them for my sister and I. So, our prom dresses, my mom made."
"I think that's probably why I love clothes so much because I watch them... and really, I love couture because of that -- because I know what it takes to make things, and the mastery in a couture dress takes my breath away -- still takes my breath away," she notes.
Kidman was accompanied inside by her husband, Keith Urban, who she gushed was racing to the event to join her after performing on Jimmy Kimmel Live!. Kidman shares that she and her two daughters with Urban -- 8-year-old Sunday and 5-year-old Faith -- are planning a quiet celebration to mark his 49th birthday on Wednesday.
"He said, 'I want nothing big. I just want the four of us together,'" she explains. "But, we've organized things. We've got stuff. The girls and I have planned it. ... I think when you're just a really close family, the last thing you want to do is go out and have some big party. He just wants to be surrounded by his girls so that's what he's getting."