updated 07/30/2012 AT 10:00 AM ET
•originally published 07/30/2012 AT 10:35 AM ET
The couple braved a crowd of enthusiastic fans to get into the building, but later looked relaxed and held hands as they mingled with around 400 guests in the garden, including actors Eddie Redmayne of My Week with Marilyn and Kit Harington of Game of Thrones.
They also watched some Olympic swimming action, and their timing was perfect, as Kidman beamed when Team Australia won the gold in the women’s 4x100 relay.
Kidman, wearing a long black dress by Azzedine Alaia and Manolo Blahnik heels, is an ambassador for the Omega brand.
She and Urban also attended the opening ceremony on Friday.
– Liz Corcoran