The 51-year-old actress took to Instagram on Sunday (21Aug16) and posted a photo of sultry-looking Cattrall alongside a touching caption.

"Happy birthday you beauty. Sending love and the very best for a perfectly marvellous, joyous, healthy and adventure filled birthday year. Your ol’ pal, fellow mischief maker and ‘sister’, Sj xxx," Parker wrote.

Cattrall also posted a message on Instagram on her birthday, sharing a photo of her dancing with a man. "Sixty and loving it!

Getting more & more interesting all the time," she captioned the snap on Sunday.

Parker and Cattrall were rumoured to have had a bitter falling out while filming the hit HBO series from 1998 to 2004 and the subsequent spin-off movies.

The TV network reportedly paid Parker, who was also an executive producer on the show, more than her co-stars Cattrall, Cynthia Nixon and Kristin Davis during the show's last season in 2004.

The pair's alleged feud was also rumoured to have halted production of the spin-off movies in 2008 and 2010.

Mother-of-three Parker opened up about the reports back in 2010, and acknowledged the all-female cast didn't always get along. "There are times when all of us have been sensitive and sometimes feelings get hurt, but I don't have any regrets about how I've treated people," she told Marie Claire.