Tamra, 52, spoked with Entertainment Tonight on Tuesday, September 3, after she brought up the infamous train rumor about Kelly, 43, on the show.
"I feel I did the viewers a favor," she said of exposing the rumor. "It was something that was told to Shannon (Beador) andVicki (Gunvalson) last year, offseason. They told me, we three knew about it. I never really thought it was gonna be brought up or an issue or anything, but then Vicki kept going, going and I'm like, 'Are you talking about the train?' Almost like, 'That stupid rumor?'"
The "train" referred to Kelly allegedly having sex with multiple men at the same time. She has since denied this ever happening.
The mother-of-four said that she takes full ownership for putting the rumor out there, but had no idea "it was gonna go that far."
Tamra said that things soured between her and Kelly later on the season though they initially started on a good note.
"Kelly does something towards the end of the (season) that is very hurtful and very damaging," the Cut Fitness owner said. "I tried not to bring too much light to it, because I really didn't want to talk about it, so I kind of kept those emotions in."
Tamra added that the only person Kelly still has as a friend on the cast is Emily Simpson. The two were the only RHOC costars missing from Shannon's end of summer party last month.
As far as making amends with Kelly, Tamra said it's not going to happen. However, she has also made the same statement about Vicki, 57, during the course of their on-again/off-again friendship.