The Australian star wore a floor-length black velvet gown with a daring thigh-high split.
Earlier in the day, Kidman stepped out dressed head-to-toe in a pristine white suit as she arrived for a panel discussion with her Lion co-star, Dev Patel, at the Picturehouse Central in London.
Kidman plays Patel's adoptive mother in the drama, which focuses on his character's journey to track down his birth mother in India using Google Earth. The film premiered at the Toronto International Film Festival last month and garnered Oscar buzz.
"My relationship with success is a bit distant because I try to stay very much in the journey," Kidman said during the Q&A session with Patel.
WATCH: Nicole Kidman Gushes Over Her Husband Keith Urban's Music, Makes Him Blush
"Winning the Oscar was a turning point, but not in terms of my life as an actor, because it was incredibly validating, but it actually symbolized loneliness to me because I didn't have anyone to share it with at that stage in my life," she explained when asked about her 2003 Best Actress Oscar win for her role in The Hours.
"I was like, 'Wow, this means I need to get my act together and I want to fall in love' so it was weird," she continued. Kidman was married to Tom Cruise for over a decade but divorced in 2001. She married country singer Keith Urban in 2006, and they are proud parents to two daughters, 8-year-old Sunday and 5-year-old Faith.
"I have an 8-year-old daughter who I’m sure is Lucille Ball in the making," Kidman gushed to the audience. "She is screwball comedy and it’s just delightful to have that belly laughing in the morning because she will do this weird physical thing and sounds and she is so free with her body and she loves to get a laugh."