The piece of advice Naomi Watts is offering Nicole Kidman in the wake of divorce from Keith Urban

This week saw the shock announcement that Nicole Kidman and Keith Urban had separated after 19 years of marriage. Shortly afterwards, on September 30, it emerged that Nicole had officially filed for divorce in a Tennessee court, citing irreconcilable differences as the cause of their split.

While neither party has yet spoken publicly about the deeper reasons behind the breakup, speculation and interest surrounding why the apparently loving couple have gone their separate ways remains extremely high.

In the wake of her long-time friend's divorce news, Naomi Watts has stepped in to offer Nicole some advice for coping with the public interest in to what, for most people, is usually a private matter.

Nicole, 58, and Naomi, 57, have been friends since their teens. Having experienced two very public breakups of her own, one with Heath Ledger and another with Liev Schreiber, Naomi is well placed to impart her knowledge.

The key advice Naomi suggests is for Nicole to be honest with the public and get all of the information about her divorce out there, to avoid ongoing speculation and possibly incorrect rumours.

Shortly after her own divorce from Liev Schreiber in 2016, Naomi spoke out about how she was feeling and coping. In conversation with The Daily Telegraph Australia, the star said, "I feel I’m in a good place in my life and I want to make sure my kids are healthy, my kids are happy and things are going to go well.

"Those are my hopes for me and for all of us," she added. Candidly, she went on to acknowledge what a difficult time divorce is for anyone, no matter what their background.

"I feel, whether you’re famous or not, transitions are scary for anybody," she said, continuing, "I feel like change is always scary, but that’s only because transition for anyone is new and you wonder how things are going to go."

Doubtlessly, Nicole will also be putting the needs of her children with Keith Urban first. The couple share daughters Sunday Rose, 17, and Faith Margaret, 14, together.

Naomi Watts' two children were aged eight and seven when she and Liev Schreiber announced their separation, and she'll likely also be on hand to offer guidance to Nicole about navigating her change in circumstances with her children.

Nicole and Naomi met as teenagers when they auditioned for the same swimsuit commercial in Sydney. The pair remained friends afterwards, and their bond has grown so strong over the years that Naomi likens Nicole to a sister.

Naomi previously supported Nicole through her first high-profile divorce from Tom Cruise in 2001. The day before their divorce was finalised, Naomi accompanied her friend to the premiere of The Others.

It's thought that Nicole is yet to comment on her divorce because she feels hurt and betrayed, having wanted to continue putting effort into their marriage to make it work.