"I was really, really scared before it happened, because we had to do the dance. I had the ring in my pocket. I had so much I wanted to say and express and tell her, and I literally said not one word," Farber later told "Good Morning America" backstage. "I said two words and that was it."
Actually, it was more like five. Farber blurted out, "I love you so much" to Slater before getting down on one knee.
But then he couldn't get the ring out.
"It felt like eternity. I was literally going to be like, 'Get it out -- quicker,'" Slater joked.
Still, the proposal couldn't have been more perfect, Slater said backstage.
"It was perfect for me," she said, before turning to Farber, "I'm so glad you decided to do that."
"It was great to share that and turn to people who were so ecstatic for you. It felt massive," she said.
Farber said he wasn't sure about popping the question on live television at first.
"And then I thought this would be perfect," he said. "Her parents are in away in England, my parents are in Australia, our families are all over the world and they'll get to see this. And I'm sure we're going to look back with our children in years to come and say this is how it all got started."
Only a few production folks were in on the big moment. "The second we started planning it, my heart was beating so fast," Farber confessed.
"I think I started to inwardly freak out when Tom gave Sasha the mic and Sasha turned to me," Slater told ABC Radio after the show. "Before he even opened his mouth, I could feel his energy and his nerves. And I lost it."
As for Slater's massive diamond and sapphire engagement ring, she picked it out because it resembled her mom's wedding ring. "I like vintage-y rings," she said.
ABC News Jason Nathanson contributed to this report.