A bit of all white: Clutching her bridesmaid's bouquet, Naomi Watts was maid of honour at her old friend Emma Cooper's wedding in Sydney today
The biggest faux pas a woman can make at a wedding - unless she's the bride, of course - is to arrive at the ceremony in a white dress.
So it's just as well that Naomi Watts was the maid of honour otherwise she might have been left feeling rather embarrassed.
As it was, she almost outshone the bride in her lacy white dress as chief bridesmaid to old friend Emma Cooper in Australia today.
The actress, 42, looked very pretty in her knee-length summer dress as she played her role as maid of honour perfectly after keeping her promise to her long time friend.
And she was just one of many stars that attended the wedding at the Shore Chapel in Sydney, as well as Naomi's husband, Scream trilogy star Liev Schreiber.
Schreiber, 43, gave the third reading at the ceremony and read Henry Lawson's After All
Congratulations! Naomi kisses her long time friend Emma Cooper after the ceremony
The bride and her best girl: Emma and Naomi walk off to the reception together laughing and holding hands
After the reading, he left the pulpit and resumed his daddy duties as he kept his and Naomi's sons, Sasha, three and two-year-old Samuel, entertained outside.
Cooper, has been a film publicist for 20 years and has befriended a lot of stars during her career, some of whom joined Naomi and Schreiber at the event.
The Mentalist star Simon Baker was there with his wife Rebecca Rigg as well as Without A Trace star Anthony La Paglia and his wife Gia Carides and Australian film director Gregor Jordan.
Leading men: Liev Schreiber and The Mentalist star Simon Baker were also guests at the wedding
This week it was revealed that Baker is the highest paid TV actor in America after signing a £280,000 an episode deal for The Mentalist.
Cooper is the daughter of NSW Father of the Year and former Taronga Zoo - where the reception was held - director Guy Cooper, who gave her away to Australian television writer Henry Cripps.
Naomi's bother Ben was the official wedding photographer, but the actress was seen filming the 120-strong wedding party for her own memories.
Cooper and Cripps, who have a six-month-old son Casper, who has Naomi for a godmother, are neighbours of the actress and Schreiber in New York.
Perfect guest: Naomi looked like she was really enjoying herself as she filmed the wedding party before keeping a watchful eye over son Sasha
Happy family: Emma and new husband Henry Cripps pose for the cameras with their son Casper and his son from his previous marriage to actress Sarah Chadwick
Emma Cooper sings Hark the herald angels sing for Christmas Eve service