Joining her wife on "The Oprah Winfrey Show" on Monday, Portia revealed she fell for Ellen from the first time she "laid eyes on her," but turning that into a relationship – one which eventually blossomed into a marriage in 2008 – took some time.
"It took me three years to actually tell her how I felt about her, because I was on 'Ally McBeal' at that time and I was not living as an openly gay person," Portia said. "I was closeted and very, very afraid that if I talked about being gay it would be the end of my career. So I wasn't about to then date the most famous lesbian in the world."
The two met "socially," according to Portia, who said she felt "that immediate draw" to Ellen.
"Over those three years, we saw each other at parties or various things, but the one time that was the most significant was at a photoshoot," Portia said. "I just walked over to say hello to her and I couldn't believe it, but she turned around and it was like an arrow was shot through my heart. I was weak at the knees and I was overwhelmed with how I felt. But then it took me about 10 months to get the courage up to do something about it."
When asked why it was important that the two women tied the knot in 2008, Portia said it was an issue of "validity."
"It's important to be married because as a gay person, it's hard to know the difference between being married and having that kind of legal stamp of validity to your relationship," she said. "It's hard to know how that actually feels until it happens and that's why it's important that everybody have that feeling."
And the actress is thrilled she made the leap.
"The thing about being a gay couple is that in the past you referred to your wife and there was quotation marks around it. There was always that chance that people would kind of snicker about it," Portia said. "Now it's fact. It's law. She's my wife. I get to say that she's my wife, and that's just the way it is."
Ellen added that their marriage has really made their relationship stronger.
"Anybody that's married knows there's a difference. It feels like you're home," she said. "There's an anchor. There's a safety. I'm gonna be with her until the day I die and I know that."