Nicole Kidman has been hailed a "queen" by her friend Naomi Watts after she turned 57

Naomi captioned the snap: "Happy birthday Nic (star emoji.) I love you so much #QUEEN (red heart emoji.)"

Other celebrities including actress Carla Gugino, 52, also sent Nicole well-wishes, writing on social media: "Happy birthday @nicolekidman (birthday cake, party popper-blowing and pink flower emojis.)"

Nicole and Naomi have been friends for decades, with Naomi reflecting on the first time they met when she spoke on Nicole's behalf at the 49th AFI Life Achievement Award Gala in April, when the actress received one of the film industry's highest awards.

Naomi said she and Nicole initially met at an audition for a 1980s swimsuit commercial and waited hours together for photographers to decide who to cast.

She added about their time together at the audition: "We covered everything - what movies we loved, what friends we had in common, our parents, schools, parties, boyfriends, teenage stuff."

Neither Nicole or Naomi landed the job with Naomi saying she missed her bus back home and Nicole helped her find her way back by paying for a taxi - which she said was typical of "the most generous person" she knows.

She went on: "Back in the Stone Age, we didn't have cell phones or Uber accounts. And no, our mums were not waiting for us outside.

"But Nic offered to spring for a taxi, and she said she would drop me on the way home, even though it was 20 minutes out of her way and it was an extra $15.00 on the meter.

"She's opened up her homes to me. She's made me feel like part of her family. She was like the sister I'd never had."

Nicole and Naomi later co-starred in the 1991 film 'Flirting', though they have not worked together since.