Adele stunned fans earlier this month after hitting the town for Drake's birthday with a very noticeably-slimmer figure.
The singer, 31, who split from husband Simon Konecki earlier this year, looked sensational in a black velvet off-the-shoulder gown as she partied with other A-listers after reportedly shedding a whopping 19 kilograms.
• How this doctor lost 40kg on his own weight loss plan
• Mother-of-three reveals success behind her epic weight loss transformation
• Woman's amazing 100kg weight loss in 11-months
• Manu Feildel reveals gruelling diet and exercise regimen behind weight loss
So how did she do it?
A source close to the star told People magazine Adele was motivated to give her health an overhaul for the sake of her seven-year-old son, Angelo and adopted a new fitness regimen earlier this year.
"At first, she was very hesitant about keeping a workout routine. It was like she was questioning if she was gonna enjoy it enough to stick with it," the insider said.
"But she has been incredibly dedicated."
Adele's routine now includes regular sessions with a personal trainer, reformer pilates classes, and workouts at the Hollywood-loving Rise Nation, a Stairmaster-inspired class.
Another source added that she's also "watching what she eats".
"She has taken a more serious interest in improving herself and is actually having a great time," the friend revealed.
Adele first surprised fans with her smaller frame when she posed alongside the Spice Girls in June during their reunion tour.
A source close to the star told The Sun at the time: "Adele has been out enjoying herself and she sees that as her priority at the moment, along with being a mum to Angelo.
"She has been loving her new workout regimen and it really works for her.
"It's a bonus that she has shifted some weight.
"Her mates are glad she's letting loose and there's nothing but good feelings towards her. She's got a new lease of life."