ET's Cameron Mathison caught up with Dion backstage, who dished all about her show-stopping white winged gown.
"Everybody thinks it's my clouds [that get in the way]," she joked. "It's my train!"
"This is Stephane Rolland Haute Couture, who is the creator of this dress, and of course Law Roach is my stylist who brought it to me," she continued. "I said, 'Forget about the rest of all the 15 racks you brought me, this is it.'"
Dion knew from the moment she saw the dress that it was the one.
"It's like when you hear a song," she explained. "This is a song for me. This is a dress that I want to wear."
The moment was just as big for Roach as it was for Celine.
"Today is the one year anniversary of the day we met, so we've had an incredible year together," he gushed. "This dress was just...I'm blown away."
"We collaborate as a team, and I brought maybe 15 dresses and this one, I knew. I did," he recalled. "I knew when she saw it and she tried it on, it was just [gasp], and when you have that [gasp], you know it's the right one."
Though Dion's style has definitely evolved throughout the last year, Roach said he isn't the one in the driver's seat.
"I didn't take her [on a journey]. We went together. She's amazing," he said. "I don't think people get to realize that she's really a student of the game. She loves fashion, and she loves clothes. She's a risk taker."
"She has no fear, and when you work with someone who is tall and beautiful and talented, and they're not afraid of putting on anything, then, you know, it' a match made in heaven," he added.