Grey's Anatomy star T.R. Knight and beau Mark Cornelsen won't be following Ellen DeGeneres and Portia De Rossi down the aisle just yet.

But they are happily living together.

"Mark just moved here from San Francisco," Knight said.

The Grey's Anatomy star dismissed rumors they're planning to wed and that he'll officiate a commitment ceremony.

"To clarify, we are not having a commitment ceremony and I am not performing a commitment ceremony," he told Us Weekly.

T.R. Knight, who's been with Mark Cornelsen for months, said May's legalization of gay marriage in California gave him an "extraordinary feeling."

"Once you are given something that you were never allowed before, you realize how much of a second class person you were before," he said.

"That is horrible and fantastic at the same time. It makes me want to sob and scream with joy all at the same time."

"The floodgates have been opened will never be closed," Cornelsen added.

Despite his youth, Mark Cornelsen, 19, has received a warm welcome from Knight's fellow Grey's Anatomy cast members.

"Someone in particular, I won't mention names told me, 'You know I like him more than I like you, right?'" the actor, 35, joked.

"They said it about three or four times so it's kind of not as funny as it was the first time anymore. They love him ... They're like, 'When is he coming?' They want him there."

"They're all wonderful and so sweet," Cornelsen said. "It's amazing."