The leading actresses of the hit U.S. show have long faced reports they don't get on, with Kim Cattrall and Sarah Jessica Parker often rumoured to be at the centre of a rift.
But their co-star Garson reveals the cast has grown so close during their time spent on the TV series and two subsequent movies, they're virtually like family.
He tells Britain's Live From Studio Five, "It's completely ridiculous. I mean, it's so ridiculous (the rift rumours).
"We've spent 15 years of our lives together literally through everything; marriages, divorces, births, deaths, everything. It's just a family."