It was an emotional moment in Boyle's incredible journey, which began April 11, 2009, when she surprised the world with her flawless performance of the iconic Les Miserables tune "I Dreamed a Dream."
ET met with Boyle later that year, after she'd already begun to receive a great deal of media attention and music offers, and the soft-spoken Scottish singer marveled at her meteoric success.
"It seems to have blown up, out of proportion," Boyle said with a laugh. "It's just unbelievable. It's fantastic."
While she didn't win her season of Britain's Got Talent -- coming in second place in the show's shocking finale -- the singer went on to sell 20 million records and has received two GRAMMY nominations.
Boyle told ET at the time that she saw her singing career -- which is a dream she's had since she was five years old -- as a way of honoring her mom.
"I wanted to do it as a kind of tribute to my mother, my late mother, who I know would want me to go through with this," Boyle shared.
On Monday, before taking the stage, Boyle opened up in a pre-taped package on America's Got Talent: The Champions, and reflected on how her life has changed over the last decade.
"Britain's Got Talent absolutely changed my life," she continued. "People saw me as somebody quite ordinary. I lived alone with my cat, Pebbles. [Now], I've sold 20-million records! Wow, even I'm overwhelmed. This has helped me fulfill the dream I've had since I was five."
Boyle has spent a great deal of the money she's earned through her record sales on charities and philanthropic endeavors, and has become a role model for so many people with big dreams, which is why she felt it was right to return to The Champions.
"I think I'm a champion for maybe those who don't have the confidence to do things, for those who don't have a voice and for those who people tend to ignore," she shared. "I feel I'm a champion for them."
The love for Boyle was evident from the moment she took the stage, as the audience burst into cheering and revelry, much to the singer's delight and appreciation. After her beautiful vocal display, which earned her the Golden Buzzer, Boyle was brought to tears by the support.
Host Terry Crews joined Boyle on stage for a hug, and asked the emotional performer how it felt to get the coveted honor, and advance immediately to the series' finals.
"I'm happy and very humbled," a choked-up Boyle said through tears of joy. "Thank you so much."
America's Got Talent: The Champions airs Mondays at 8 p.m. ET/PT on NBC.