Yet playing a lesbian is a first for Portia. "I am a lesbian playing a lesbian" says the blonde actress, "But she's a different woman than I am, so the most surprising thing is how emotional it's been for me."
It's been three years since the leggy blonde went public about her relationship with Ellen de Generes and at first she worried she'd be typecast as a lesbian if she took the Nip/Tuck role.
Yet her girlfriend Ellen urged her to do it.
"My relationship with Ellen is so public, and I thought, 'Am I going to play a romantic lead again?' I had that one moment of, 'Does this mean I'll be typecast as a lesbian?'" Portia said.
"And Ellen turned to me and said, 'So what?' And I thought, 'Oh, yeah, right, so what?'"
Yet there were no such reservations for co-star Joely.
Joely, 42, said: "I have no problems kissing women. It's not the first time I have done lesbian scenes.
"I have heard Ellen was jealous. She has been on set. She is great and Portia is lovely."
The actress added, "I think playing a lesbian turns men on. When my character Julia was the boring, married housewife, always chopping vegetables, people were sweet and lovely.
"But now I'm playing her as a sexy ***** with a big padded bra and a short skirt, I get a very different reaction.
"I think men respond to the sexiness of two women being together."