Nicole Richie lost her baby weight by dancing to Jay-Z songs.
The socialite - who has two-month-old son Sparrow with her partner Joel Madden - claims she has lost the excess pounds gained through her pregnancy by dancing to the hip hop star.
Writing at the 'Run This Town' hitmaker's concert at Los Angeles' Pauley Pavilion on Sunday, Richie posted on her Twitter page: "I've lost 10lbs from dancing!! H to the izzo. V to the izza!! (sic)."
The 28-year-old - who also has 21-month-old daughter Harlow with Joel - was dancing so much at the bash she would need help moving the next day.
She quipped: "I'm gonna need crutches tomorrow!"