The couple, who met in 2005 at the Metropolitan Museum of Art's Costume Institute Gala, have two children together.
Blonde Naomi, 45, who currently stars in Diana, said that she was 'a lot more ballsy' with Liev than she would normally be, making sure that he didn't leave the party without her number.
'Normally I want a guy to make the first move,' Naomi told Allure magazine.
'Then he got up to say he was leaving and i was like, "Oh s***. Probably another couple years are going to pass by." I was wildly attracted to him and his work, so I said something cheeky as he was about to walk out.'
And according to the actress, she openly asked if the fellow actor would like her digits, which broke the ice between them.
'He texted me five minutes later saying, "Would you like to go for a drink now?' And I said, "No, I'll meet you for breakfast tomorrow.'
The pair have been dating ever since, and have gone onto have Alexander and Samuel together.
Although less well known than his famous other half, Liev, 46, has also had a successful acting career, getting his big break as the murderer in the Scream trilogy, but also starring in stage productions of Shakespeare plays and also in film The Painted Veil - in which Watts also starred.