Lady Gaga crying while swarmed by her supporters at the American Music Awards

Lady Gaga was brought to tears at the American Music Awards -- not by receiving some trophy, but by her fans serenading her with her latest hit song.

Gaga was leaving Microsoft Theater Sunday night when she got swarmed by a throng of her supporters, who joined in on a group sing-a-long of her single "Million Reasons" ... which she had performed that night.

The sort of on-key encore, clearly struck a chord with her.

With global album and single sales of 27 million and 146 million respectively, as of January 2016, she is one of the best-selling musicians of all time. Her achievements include twelve Guinness World Records, three Brit Awards, and six Grammy Awards. She is also the first artist to win the Songwriters Hall of Fame's Contemporary Icon Award.

Other accolades include a Fashion Icon lifetime achievement award from the Council of Fashion Designers of America (2011), regular appearances on Billboard's Artists of the Year lists and Forbes's power and earnings rankings. In 2013, Gaga finished second on Time's readers' poll of the most influential people of the past ten years, while in 2015, she was named Billboard's Woman of the Year.

She is known for her philanthropic work and social activism, including LGBT rights and her own non-profit organization, the Born This Way Foundation, which focuses on promoting youth empowerment and combating bullying.