The actress arrived at St Frances Xavier Church in Lavender Bay with her husband Keith Urban and their two daughters.
They were joined by extended family and friends as they paid tribute to the matriarch of the family.
Kidman won the best actress award for her role in Babygirl, but was unable to be there to accept the award.
Instead, the film’s director Halina Reijn read out a letter on her behalf, which relayed that Kidman had arrived at the festival, only to find out “shortly after that my beautiful, brave mother, Janelle Ann Kidman, has just passed”.
“I’m in shock and I have to go to my family, but this award is for her,” Kidman said in her statement.
“She shaped me, she guided me and she made me.
“I am beyond grateful that I get to say her name to all of you through Halina.
“The collision of life and art is heartbreaking, and my heart is broken.”