Sarah Jessica Parker has wished happy birthday to her "sister" Kim Cattrall.

Sarah Jessica Parker

Sarah Jessica Parker

The 51-year-old actress celebrated her 'Sex In The City' co-star's 60th birthday with a sweet message on Instagram.

She wrote: "Happy birthday you beauty @kimcattrall. Sending love and the very best for a perfectly marvelous, joyous, healthy and adventure filled birthday year. Your ol' pal, fellow mischief maker and "sister", Sj xxx (sic)"

And Sarah and Kim might not have even known each other as the blonde beauty - who played Carrie Bradshaw in the hit show - previously admitted she nearly turned down the programme because she was concerned about "nudity and language issues".

She wrote: "He [her agent Kevin Huvane] called me up and said, 'Darren Star reached out to me. 'He's written this pilot [Sex and the City] and tells me he wrote it with you in mind - you were in his head when he was writing it. I'm going to send it to you. I've read it. I think it's really good. You should meet with him.'

"And I said, 'Really? I feel like I've got it all right now. I can do a play, then do a movie, then do a play, then do a movie. There's a lot of flexibility. What could be better? Do I really want to go back to making a television series when I'm maybe held hostage signing a long-term contract?'

"I met with Darren, and there were a couple of concerns that I had -- like I really wasn't keen on doing nudity and language issues -- but Kevin continued to say to me, 'This is different. You have never done anything like this before. No one's ever done a part like this. Do this.'"