Christina Aguilera was a sight to behold during the opening night of her Las Vegas residency -- showing off an incredible 40 lb. weight loss.
The singer belted out her catalog of hits Saturday from The Voltaire at The Venetian, Xtina's strong and slender figure was front and center in a series of tight leotards and thigh-high boots.
After years of scrutiny for her fluctuating weight, XTINA's maintaining a healthy physique ... previously admitting she hated being skinny and loved her booty.
She's clearly now found the secret to maintaining those curves ... and says it's helped with a balanced diet and dedicating herself to boxing, strength training and cardio workouts.
It wasn't all smooth sailing though ... she restricted her daily food intake to 1600 calories on the Rainbow Diet after welcoming her son Max in 2008.
However, in a turn in 2020, she said she was dunzo with dieting ... focusing on clean eating and consuming fewer sugary snacks.
No doubt, her high-energy residency performances will also help keep her in shape.