McKellar started dating Jeremy Miller -- who co-starred on Growing Pains with Bure's brother, Kirk Cameron -- shortly after he broke up with Bure.
"I remember the phone call I got from Jeremy Miller saying, 'We're breaking up because I have a new girlfriend and her name is Danica!'" Bure said on Monday night's episode.
But it was so long ago, both women told E! News backstage that they were way past their teenage love triangle.
"I knew that Candace's was Jeremy's ex-girlfriend. I mean, look, we were 13. Nothing was happening," McKellar said. "But like, I didn't know that he broke up with her for me. Like, I really didn't know that until last week!"
"We were like 11, I was not allowed to date until I was 16, so you can imagine it was a really big love triangle," Bure added.
Miller told Access Hollywood that he could barely remember the dueling romances:
“I honestly don’t remember. It was so long ago. I was 12,” the 37-year-old said. “It was my impression that Candace and I had been distant for a while before I started talking to Danica.”