From one stage to the next, Nicole Scherzinger showed all her millions what it takes to be a Broadway star -- staying' fit and slaying a revealing workout set!

The singer-actress has been a busy lady on Broadway -- playing Norma Desmond in the stage adaptation of the highly-acclaimed "Sunset Boulevard" -- and shared a workout vid which entailed a series of intense exercises!

Check it out ... Nicole got down on her back and busted out some crunches, while holding a dumbbell over her head.

That booty must've been on fire, because she demonstrated glute bridges with some big ole' weights!

From her back to her feet, she was heatin' up and slid out of her crop top for some tricep pushdowns, all in her sports bra!

Feelin' the burn yet? Get in tip-top shape with our photo gallery and see Scherzinger in action!