The "Princess of Pop," who turns 37 on Dec. 2, regularly showers her nearly 20 million followers with pics and videos of her intense gym sessions and somehow manages to look absolutely incredible in all of them.
Her "Hit Me One More Time" heyday may have passed, but the pop icon still plays sold out shows all over the world. That relentless workout regimen surely helps her power through performances.
Needless to say, no one's wondering how this mom-of-two has the body of model nearly half her age.
Enjoy Brit's hottest fitness moments in the gallery above, and see all of her fiery workout clips below: